Exercises
Theoretical Questions
1. What is
a function? List out the advantages of functions.
A function is a routine or a set of instruction or code
that performs a specific task and can be processed independently.
When the program passes control to a function the
function perform that task and returns control to the instruction following the
calling instruction. The most important reason to use the function is make
program handling easier as only a small
part of the program is dealt with at a time.
Advantages of
Functions:
i) The length
of a source program can be reduced by
using functions at appropriate places. This factor is particularly critical
with microcomputers where memory space is limited.
ii) It is easy to
locate and isolate a faulty function for further investigations.
iii) A function
may be used by many other programs. This means that a C programmer can build on
what others have already done, instead of starting all over again from scratch.
iv) It facilitates top-down modular programming. In this
programming style, the high level logic of the overall problem is solved first
while the details of each lower-level function are addressed later.
2. What do
you mean by library function? How list is it different from user-defined
function ? or
What is
the difference between a library funciton and user-defined function ?
Library functions are pre defined functions. Inorder to
ease the work of the user, the developer provides some built in functions. For
some operations we need not write our own code. We can simply use one of those
library functions to get our work done.
The difference between the library and user-defined
functions is that we do not need to write a code for a library function. It is
already present inside the header file which we always include at the beginning
of a program. You just have to type the name of a function and use it along
with the proper syntax. Printf, scanf are the examples of a library function.
Whereas, a user-defined function is a type of function in
which we have to write a body of a function and call the function whenever we
require the function to perform some operation in our program.
A user-defined function is always written by the user,
but later it can be a part of 'C' library. It is a major advantage of 'C'
programming.
3. What are
the different components of functions? Explain.
A function usually has three components. They are:
1.
Function
Prototype/Declaration:
Function declaration is a
statement that informs the compiler about
Name of the function
Type of arguments
Number of arguments
Type of Return value
Syntax for function
declaration
returntype function_name
([arguments type]);
2.
Function Definition:
Function definition consists
of the body of function. The body consists of block of statements that specify
what task is to be performed. When a function is called, the control is
transferred to the function definition.
Syntax for function definition:
returntype function_name
([arguments])
{
statement(s);
... ... ...
}
Return Statement
A return statement is used
to return values to the invoking function by the invoked function. The data
type of value a function can return is specified during function declaration. A
function with void as return type don't return any value. Beside basic data
type, it can return object and pointers too. A return statement is usually
place at the end of function definition or inside a branching statement.
Syntax of return statement
return value;
3.
Function Call:
A function call can be made
by using a call statement. A function call statement consists of function name
and required argument enclosed in round brackets.
Syntax for function call
function_name ([actual
arguments]);
4. Explain
different types of user-defined functions with an example.
Ø There can be 4 different types of user-defined functions,
they are:
1.
Function with no
arguments and no return value
Such functions can either be
used to display information or they are completely dependent on user inputs.
Ex:
#include<stdio.h>
void greatNum(); // function declaration
int main()
{
greatNum(); // function call
return 0;
}
void greatNum() // function definition
{
int i, j;
printf("Enter 2 numbers that you want
to compare...");
scanf("%d%d", &i, &j);
if(i > j) {
printf("The greater number is:
%d", i);
}
else {
printf("The greater number is:
%d", j);
}
}
2.
Function with no
arguments and a return value
In this method, We won’t
pass any arguments to the function while defining, declaring, or calling the
function. This type of function will return some value when we call the
function from main() or any sub function.
Ex:
#include<stdio.h>
int greatNum(); // function declaration
int main()
{
int result;
result = greatNum(); // function call
printf("The greater number is:
%d", result);
return 0;
}
int greatNum() // function definition
{
int i, j, greaterNum;
printf("Enter 2 numbers that you want
to compare...");
scanf("%d%d", &i, &j);
if(i > j) {
greaterNum = i;
}
else {
greaterNum = j;
}
// returning the result
return greaterNum;
}
3.
Function with
arguments and no return value
This method allows us to pass
the arguments to the function while calling the function. But, This type of
function will not return any value when we call the function from main () or
any sub function.
Ex:
#include<stdio.h>
void greatNum(int a, int
b); // function declaration
int main()
{
int i, j;
printf("Enter 2 numbers that you want
to compare...");
scanf("%d%d", &i, &j);
greatNum(i, j); // function call
return 0;
}
void greatNum(int x, int
y) // function definition
{
if(x > y) {
printf("The greater number is:
%d", x);
}
else {
printf("The greater number is:
%d", y);
}
}
4.
Function with
arguments and a return value
This Types of Functions in C
program allows the user to enter 2 integer values. And then, We are going to
pass those values to the user-defined function to multiply those values and
return the value using the return keyword.
Ex:
#include<stdio.h>
int greatNum(int a, int
b); // function declaration
int main()
{
int i, j, result;
printf("Enter 2 numbers that you want
to compare...");
scanf("%d%d", &i, &j);
result = greatNum(i, j); // function call
printf("The greater number is:
%d", result);
return 0;
}
int greatNum(int x, int
y) // function definition
{
if(x > y) {
return x;
}
else {
return y;
}
}
5. Explain
recursive function with an example.
A function that calls itself is known as a recursive
function. And, this technique is known as recursion. This enables the function to repeat itself several times,
outputting the result and the end of each iteration. Below is an example of a
recursive function.
Ex: The following example
calculates the factorial of a given number using a recursive function
#include <stdio.h>
unsigned long long int factorial(unsigned int i) {
if(i <= 1) {
return 1;
}
return i *
factorial(i - 1);
}
int main() {
int i = 12;
printf("Factorial of %d is %d\n", i, factorial(i));
return 0;
}
Practical based Questions
1. Write a
c program to input a number and calculate its reverse using function.
#include<stdio.h>
int
findReverse(int n)
{
int sum=0;
while (n!=0)
{
sum = sum*10 +
n%10;
n /= 10;
}
return sum;
}
int main()
{
int number,
reverse;
printf("Enter a positive interger: ");
scanf("%d", &number);
reverse =
findReverse(number);
printf("The
reverse of %d is: %d", number, reverse);
return 0;
}
2. Write a
c program to find the sum of ‘n’ integer numbers using the function.
#include<stdio.h>
int sum(int n)
{
int add = 0;
for(int i=1;
i<=n; i++)
{
add += i;
}
return add;
}
int main()
{
int range,
result;
printf("Upto which number you want to find sum: ");
scanf("%d", &range);
result =
sum(range);
printf("1+2+3+….+%d+%d = %d",range-1, range, result);
}
3. Write a
c program to input a number and check if it is even or odd using the function.
#include <stdio.h>
int isEven(int num)
{
return !(num
& 1);
}
int main()
{
int num;
printf("Enter any number: ");
scanf("%d", &num);
if(isEven(num))
{
printf("The number is even.");
}
else
{
printf("The number is odd.");
}
return 0;
}
4 Write a
c program to input principle, rate and time and calculate simple interest using
the function.
#include<stdio.h>
void main()
{
float p;
int t,r;
printf(“Enter principal:\n”);
scanf(“%d”,&p);
printf(“Input rate of interest:\n”);
scanf(“%d”,&r);
printf(“Enter time in years:\n”);
scanf(“%d”,&t);
printf(“simple interest =rs. %f”,simple (p, r, t));
}
// simple interest function
float simple(float p, int r, int t)
{
float si=(p * r * t) / 100;
return (si);
}
5. Write a c
program to store Kathmandu Valley’s 7 days maximum and minimum temperature (in
centigrade) and callculate the average, maximum, minimum temerature using
funciton and print 7 days temperature, miimum, maximum and average temperature
using any high-level programming language.
6. Write a
c program to calculate the factorial of a given number using functions.
#include<stdio.h>
#include<math.h>
void main()
{
//clrscr();
printf("Enter a Number to Find Factorial: ");
fact();
getch();
}
fact()
{
int
i,fact=1,n;
scanf("%d",&n);
for(i=1;
i<=n; i++)
{
fact=fact*i;
}
printf("\nFactorial of a Given Number is: %d ",fact);
return fact;
}
7. Write a
c program using a user-defined function to calculate y raise to power x.
#include <stdio.h>
#include <conio.h>
#include <math.h>
long int yraisex(int, int);
void main()
{
int bese,exp;
long int result;
clrscr();
pr1ntf(”\n Input base and exponent values:-);
scanf("%d%d",&base,&exp);
result=yraisex(base,exp);
printf("\n Result = %ld",result);
getch();
long int yraisex(int x,int y)
{
long int z;
z=pow(x,y);
return (z);
}
8. Write a
c program to calculate a term of Fibonaci series using a recursive function.
#include<stdio.h>
int Fibonacci(int);
int main()
{
int n, i = 0,
c;
scanf("%d",&n);
printf("Fibonacci series\n");
for ( c = 1 ; c
<= n ; c++ )
{
printf("%d\n", Fibonacci(i));
i++;
}
return 0;
}
int Fibonacci(int n)
{
if ( n == 0 )
return 0;
else if ( n ==
1 )
return 1;
else
return (
Fibonacci(n-1) + Fibonacci(n-2) );
}
9. Write a
c program to calculate the factorial of a given number using recursive
function.
#include<stdio.h>
long int multiplyNumbers(int n);
int main() {
int n;
printf("Enter a positive integer: ");
scanf("%d",&n);
printf("Factorial of %d = %ld", n, multiplyNumbers(n));
return 0;
}
long int multiplyNumbers(int n) {
if (n>=1)
return
n*multiplyNumbers(n-1);
else
return 1;
}
10 Write a c
program with function and input menu from the keyboard and activate these
functions:
i.
print area of a circle ( )
ii.
reverse string()
#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<math.h>
float area(int r)
{
return(22*r*r)/7;
}
void reverse(char c);
void main()
{
int r,choice;
char c[25];
float result;
clrscr();
printf("enter 1 for area. 2 for reverse\n");
printf("enter your choice:");
scanf("%d",&choice);
switch(choice)
{
case 1: {
printf("enter the radius:");
scanf("%d",&r);
result=area(r);
printf("the area of circle is %f",result);
break;
}
case 2: {
printf("enter the strin:g");
scanf("%s",&c);
strrev(c);
printf("the reversed string is: %s",c);
break;
}
default:
printf("wrong input");
}
getch();
}
end
Exercises
Theoretical Questions
1. Define
the term pointer with its key features.
A
pointer is a variable whose value is the address of another variable, i.e.,
direct address of the memory location. Like any variable or constant, you must
declare a pointer before using it to store any variable address. The general
form of a pointer variable declaration is −
type *var-name;
Uses and features of
pointer:
Ø Pointers provide direct access to memory
Ø It provides a way to return more than one value to the function.
Ø Reduces the storage space and complexity of the program.
Ø Reduces the execution time of the program.
Ø Provides an alternative way to access array elements.
Ø It allows us to perform the dynamic memory allocation.
2. Write
down the advantages and disadvantages of using a pointer.
Advantages
·
Pointers provide
direct access to memory
·
Pointers provide a way
to return more than one value to the functions
·
Reduces the storage
space and complexity of the program
·
Reduces the execution
time of the program
·
Provides an alternate
way to access array elements
·
Pointers can be used
to pass information back and forth between the calling function and called function.
Disadvantages
·
Uninitialized pointers
might cause segmentation fault.
·
Dynamically allocated
block needs to be freed explicitly.
Otherwise, it would lead to memory leak.
·
Pointers are slower
than normal variables.
·
If pointers are
updated with incorrect values, it might lead to memory corruption.
3. What do
you mean by the term address of (&) and indirection (*) operator?
The address operator (&) can be used
with an lvalue, such as a variable, as in &var. This expression yields the
address of variable var, i.e., a pointer to it. Note that the address operator
cannot be used with constants and non-lvalue expressions. Thus, the expressions
&100,&(a+5) and &'X' are invalid. If the type of variable var is T,
the expression &var returns a value of type T *,i.e., a pointer to type T.
We can use the addressoperator to obtain
its address, whatever it may be. This address can be assigned to a
pointervariable of appropriate type so that the pointer points to that
variable.
The dereference/indireciton operator (*)
is a unary prefix operator that can be used with any pointer variable, as in
*ptr_var. This expression yields the value of the variable pointed at by that
pointer. Although the symbol for the dereference operator is the same as that
of the multiplication operator, its use is unambiguous from the context as the
latter is a binary infix operator used, as in expr1 * expr2.
4. Explain
the importance of pointer in C programming. Illustrate pointer operations with
an example. Show the relation between array and pointers with example.
The importance of pointer is given bellow:-
Ø It is more efficient to handling data stored in array or
table.
Ø Pointer can be used to turn multiple values from a
function via function arguments.
Ø Pointer permits references to functions and there by
facilitating passing from function as arguments to other functions.
Ø Pointer allows dynamic memory management.
Ø It provides an efficient to manage structures, link
list, stacks and binary trees.
Ø It reduces length and complexity of program.
Ex:
#include <stdio.h>
int main()
{
int num = 10;
printf("Value of variable num is: %d", num);
printf("\nAddress of variable num is: %p",
&num);
return 0;
}
Arrays and pointers are closely related in C. In fact an
array declared as int A[10];
can be accessed using its pointer representation. The
name of the array A is a constant pointer to the first element of the array. So
A can be considered a const int*. Since A is a constant pointer, A = NULL would
be an illegal statement. Arrays and pointers are synonymous in terms of how they
use to access memory. But, the important difference between them is that, a
pointer variable can take different addresses as value whereas, in case of
array it is fixed.
Ex:
#include <stdio.h>
int main() {
int i, x[6], sum
= 0;
printf("Enter 6 numbers: ");
for(i = 0; i <
6; ++i) {
scanf("%d", x+i);
sum +=
*(x+i);
}
printf("Sum
= %d", sum);
return 0;
}
5. Differentiate
between structures and pointers with example.
Structures are basically “named
data records”.
The
structure is a “blueprint” of how to store the data in memory, the pointer is
the location of the data in memory
an example would be for a “person” structure,
you might have:
struct person
{
int
dateOfBirth;
char *
firstName;
char *
lastName;
int socialSecurityNumber;
};
Whereas,
A pointer is the address of that structure (or anything
else) in memory.
The idea of a pointer is that rather than pass the data
around your program, you pass the location of the data.
6. What are
the differences between array and pointer?
Difference between Arrays and pointers
|
Array |
Pointer |
|
·
An array is a single, pre-allocated
chunk of contagious element (all the same type), fixed in size and
location. |
·
A pointer is a place in memory that
keeps the address of another place inside.
|
|
·
They are static in nature. Once the
memory is allocated, it cannot be resized or freed dynamically according to
users requirement. |
·
Pointer is dynamic in nature. The
memory allocation can be resized or freed later at any point in time. |
|
·
Arrays are allocated at compile time
i.e at the time when programmer is writing program |
·
Pointers are allocated at runtime i.e
after executing program. |
|
·
An array size decides the number of
variables it can store. |
·
A pointer variable can store the
address of only one variable. |
7. Differentiate
between call by value and call by reference.
|
Call by value |
call by reference |
|
·
While calling a function, when you
pass values by copying variables, it is known as "Call By Values." |
·
While calling a function, in
programming language instead of copying the values of variables, the address
of the variables is used it is known as "Call By References. |
|
·
In this method, a copy of the
variable is passed. |
·
In this method, a variable itself is
passed. |
|
·
Does not allow you to make any
changes in the actual variables. |
·
Allows you to make changes in the
values of variables by using function calls. |
|
·
Original value not modified |
·
The original value is modified. |
Practical based Questions
1. Write a
c program to calculate two numbers using pointers.
#include <stdio.h>
int main()
{
int first,
second, *p, *q, sum;
printf("Enter two integers to add\n");
scanf("%d%d", &first, &second);
p = &first;
q = &second;
sum = *p + *q;
printf("Sum
of the numbers = %d\n", sum);
return 0;
}
2. Write a
c program to calculate factorial of
given numbers using pointers.
#include<stdio.h>
#include<conio.h>
void findFactorial(int,int *);
int main(){
int
i,factorial,num;
printf("Enter a number: ");
scanf("%d",&num);
findFactorial(num,&factorial);
printf("Factorial of %d is: %d",num,*factorial);
return 0;
}
void findFactorial(int num,int *factorial){
int i;
*factorial =1;
for(i=1;i<=num;i++)
*factorial=*factorial*i;
}
Getch();
}
3. Write a
c program to swap two numbers using call by reference.
#include <stdio.h>
#include<conio.h>
void swap(int*, int*);
int main()
{
int x, y;
printf("Enter the value of x and y\n");
scanf("%d%d",&x,&y);
printf("Before Swapping\nx = %d\ny = %d\n", x, y);
swap(&x,
&y);
printf("After Swapping\nx = %d\ny = %d\n", x, y);
return 0;
}
void swap(int *a, int *b)
{
int temp;
temp = *b;
*b = *a;
*a = temp;
}
Getch();
}
4. Write a
c program to input principle, rate and time and calculate simple interest suing
pointers.
#include<stdio.h>
#include<conio.h>
void main()
{
float
p,r,t,si,*p1,*p2,*p3;
clrscr();
p1=&p;
p2=&r;
p3=&t;
printf("Enter
principal amount: ");
scanf("%f",p1);
printf("Enter
rate of interest: ");
scanf("%f",p2);
printf("Enter
time: ");
scanf("%f",p3);
si=(*p1**p2**p3)/100;
printf("\n\nSimple Interest =
%f",si);
getch();
}
5. Write a
c program to check whether a number is even or odd using pointers.
#include<stdio.h>
#include<conio.h>
void main()
{
int a;
int *p1;
p1=&a;
clrscr();
printf("Enter The Number You Want to Check \n\n");
scanf("%d",&a);
if(*p1%2==0)
{
printf("Number Is even \n");
}
else
{
printf("Number Is odd\n");
}
getch();
}
6. Write a
c program to input a number, calculate its square and display the memory
address of the inputted number and the square.
#include<stdio.h>
#include<conio.h>
void main()
{
int num;
int square;
clrscr();
printf("enter the number:");
scanf("%d",&num);
square=num*num;
printf("the square of %d is %d\n",square);
printf("the address of num is %p\n",&num);
getch();
}
7. Write a
c program to input a number and display its multiplication table using
pointers.
# include < stdio.h >
int main( )
{
int num, i ;
int *ptr ;
printf(" Enter the number for Print multiplicaiton
Table: ") ;
scanf("%d ",& num) ;
ptr = &num ;
printf("\n Multiplicaiton Table of %d are
:\n",num) ;
for (i = 1; i <= 10 ; i++ )
{
printf("\n %d ",(*ptr * i)) ;
}
return ( 0 );
}
Exercises
Theoretical Questions
1. What is
a data file? Write down the syntax to create a new file.
A data file is generally used as real-life applications
that contain a large amount of data.
C programming provides built-in support to create, read,
write and append data to file. To perform any operation on file we use a
built-in FILE structure. You need to create pointer to FILE type.
Syntax:
FILE * fPtr;
2. List our
all the file manipulation functions with examples of each.
There are
4 basic operations that can be performed on any files in C
programming language. They are,
1. Opening/Creating a file
2. Closing a file
3. Reading a file
4. Writing in a file
fopen() – To
open a file
Declaration:
FILE *fopen (const char *filename, const char *mode)
fopen() function is used to open a file to perform
operations such as reading, writing etc. In a C program, we declare a file
pointer and use fopen() as below. fopen() function creates a new file if the
mentioned file name does not exist.
FILE *fp;
fp=fopen (“filename”, ”‘mode”);
Where,
fp – file pointer to the data type “FILE”.
filename – the actual file name with full path of the
file.
mode – refers to the operation that will be performed on
the file. Example: r, w, a, r+, w+ and a+. Please refer below the description
for these mode of operations.
fclose() –
To close a file
Declaration: int fclose(FILE *fp);
fclose() function closes the file that is being pointed
by file pointer fp. In a C program, we close a file as below.
fclose (fp);
fgets() – To
read a file
Declaration: char *fgets(char *string, int n, FILE *fp)
fgets function is used to read a file line by line. In a
C program, we use fgets function as below.
fgets (buffer, size, fp);
where,
buffer – buffer to
put the data in.
size – size of the buffer
fp – file pointer
fprintf() –
To write into a file
Declaration:int fprintf(FILE *fp, const char *format, …);
fprintf() function writes string into a file pointed by
fp. In a C program, we write string into a file as below.
fprintf (fp, “some data”); or
fprintf (fp, “text %d”, variable_name);
3. Write
the functions of rename () and remove () with example.
The remove( ) and rename( ) functions in the stdio.h
library
can be used to manipulate files.
The remove( ) function deletes a file from memory.
//Remove a file
Using remove() function in C, we can write a program
which can destroy itself after it is compiled and executed.
#include<stdio.h>
#include<stdlib.h>
int main(int c, char *argv[])
{
printf("By
the time you will compile me I will be destroyed \n");
remove(argv[0]);
return 0;
}
// This code is contributed by MAZHAR IMAM KHAN.
The rename( ) function takes the name of a file as its
argument, and the new name of the file as a second argument. For example,
rename("myfile.dat", "newfile.dat"); renames the file myfile.dat as
newfile.dat. The rename( ) function also
requires C-style string arguments.
// C program to demonstrate use of rename()
#include<stdio.h>
int main()
{
// Old
file name
char
old_name[] = "geeks.txt";
char
new_name[] = "geeksforgeeks.txt";
int value;
value =
rename(old_name, new_name);
if(!value)
{
printf("%s",
"File name changed successfully");
}
else
{
perror("Error");
}
return 0;
}
4. Explain
the functions of fprint() and fscanf() with example.
The fprintf() function is used to write set of characters
into file. It sends formatted output to a stream.
Ex:
#include <stdio.h>
main(){
FILE *fp;
fp =
fopen("file.txt", "w");//opening file
fprintf(fp,
"Hello file by fprintf...\n");//writing data into file
fclose(fp);//closing file
}
The fscanf() function is used to read set of characters
from file. It reads a word from the file and returns EOF at the end of file.
#include <stdio.h>
main(){
FILE *fp;
char
buff[255];//creating char array to store data of file
fp =
fopen("file.txt", "r");
while(fscanf(fp,
"%s", buff)!=EOF){
printf("%s
", buff );
}
fclose(fp);
}
5. Define
the terms FILE and EOF in file handling.
The collection of
different data or information or instructions wich is stored in secondary
storage devices under a unique file name is known as file.
End
Of File or EOF is a specific designation for a file marker that indicates the
end of a file or data set.
6. Describe
any five ‘file handling function’ with examples.
File
handling is a process to create a data file, write data to the data file and
read data from the specified data file.
fopen():The
fopen() function is used to open a file and associates an I/O stream with it.
This function takes two arguments. The first argument is a pointer to a string
containing name of the file to be opened while the second argument is the mode
in which the file is to be opened.
Syntax:
FILE
*fopen(const char *path, const char *mode);
fread()and
fwrite():The functions fread/fwrite are used for reading/writing
data from/to the file opened by fopen function. These functions accept three
arguments. The first argument is a pointer to buffer used for reading/writing
the data. The data read/written is in the form of ‘nmemb’ elements each ‘size’
bytes long.
Syntax:
size_t
fread(void *ptr, size_t size, size_t nmemb, FILE *stream);
size_t
fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);
fseek():The
fseek() function is used to set the file position indicator for the stream to a
new position. This function accepts three arguments. The first argument is the
FILE stream pointer returned by the fopen() function. The second argument
‘offset’ tells the amount of bytes to seek. The third argument ‘whence’ tells
from where the seek of ‘offset’ number of bytes is to be done. The available
values for whence are SEEK_SET, SEEK_CUR, or SEEK_END.
Syntax
int
fseek(FILE *stream, long offset, int whence);
fclose():The
fclose() function first flushes the stream opened by fopen() and then closes
the underlying descriptor. Upon successful completion this function returns 0
else end of file (eof) is returned. In case of failure, if the stream is
accessed further then the behavior remains undefined.
Syntax:
int
fclose(FILE *fp);
ex:
#include<stdio.h>
#include<string.h>
#define
SIZE 1
#define
NUMELEM 5
int
main(void)
{
FILE* fd = NULL;
char buff[100];
memset(buff,0,sizeof(buff));
fd =
fopen("test.txt","rw+");
if(NULL == fd)
{
printf("\n fopen() Error!!!\n");
return 1;
}
printf("\n File opened successfully
through fopen()\n");
if(SIZE*NUMELEM !=
fread(buff,SIZE,NUMELEM,fd))
{
printf("\n fread()
failed\n");
return 1;
}
printf("\n Some bytes successfully
read through fread()\n");
printf("\n The bytes read are
[%s]\n",buff);
if(0 != fseek(fd,11,SEEK_CUR))
{
printf("\n fseek()
failed\n");
return 1;
}
printf("\n fseek() successful\n");
if(SIZE*NUMELEM !=
fwrite(buff,SIZE,strlen(buff),fd))
{
printf("\n fwrite()
failed\n");
return 1;
}
printf("\n fwrite() successful, data
written to text file\n");
fclose(fd);
printf("\n File stream closed through
fclose()\n");
return 0;
}
7. Write a
program which reads name, roll-number and age from a file named “student.dat”
and display them.
#include
<stdio.h>
#include
<conio.h>
void
main ()
{
char
name [30], add [20],
long
int phone;
FILE
*fp;
fp =
fopen ("STUD.DAT", "w+");
for
(I = 0; i<5; i++)
{
printf
("Enter anme : /n");
scanf
("%s", name [i]);
printf
("Enter address : /n");
scanf
("%s", add [i]);
printf
("Enter phone : /n");
scanf
("%ld", &phone [i]);
fprintf
(fp, "%s%s%d", name[i],phone[i]);
}
rewind
(fp); //Sets the file pointer at the beginning of a file
for
(I = 0; i<5; i++)
{
fscanf
(fp, "%s %s %ld', name, add, &phone);
printf
("Name = %s /t Address = %s /t phone = % /d", name [i], add [i],
phone [i];
}
fclose
(fp);
getch
();
}
8. Describe
fscanf and fprintf function.
Refer
question number 4
Practical based Questions
1. Write a
program in C for writing data in the file.
#include<stdio.h>
#include<conio.h>
void
main()
{
FILE *fptr;
char name[20];
int age;
float salary;
fptr = fopen("emp.txt",
"w");
if (fptr == NULL)
{
printf("File does not
exist.\n");
return;
}
printf("Enter the name:\n");
scanf("%s", name);
fprintf(fptr, "Name = %s\n", name);
printf("Enter the age:\n");
scanf("%d", &age);
fprintf(fptr, "Age = %d\n", age);
printf("Enter the salary:\n");
scanf("%f", &salary);
fprintf(fptr, "Salary = %.2f\n", salary);
fclose(fptr);
}
2. Write a
c program to show data writing and reading operation to/from a data file.
#include <stdio.h>
#include <stdlib.h>
#define DATA_SIZE 1000
int main()
{
char
data[DATA_SIZE];
FILE * fPtr;
fPtr =
fopen("data/file1.txt", "w");
if(fPtr ==
NULL)
{
printf("Unable to create file.\n");
exit(EXIT_FAILURE);
}
fgets(data,
DATA_SIZE, stdin);
fputs(data,
fPtr);
fclose(fPtr);
printf("File created and saved successfully. :) \n");
return 0;
}
3. Write a
c program to enter name, roll-number and marks of 10 students and store them in
the file.
#include<stdio.h>
#include<conio.h>
Void main()
{
File *fp;
Char name[10][20];
Int roll_number[10], marks[10];
Int I, n;
Fp=fopen("c:\play.dat","w");
For(i=0;i<10;i++)
{
Printf("enter roll number:");
Scanf("%d", &roll_number[i]);
Printf("enter name");
Scanf("%s", name[i]);
Printf("enter marks");
Scanf("%d", &marks[i]);
Fprintf(fp, %d %s %d", roll_number[i], name[i],
marks[i]);
}
Fclose(fp);
Getch();
}
4. Write a
c program to store std-no, name and mark of ‘n’ students in a data file.
Display the records in appropriate format reading from the file.
#include
<stdio.h>
#include
<conio.h>
#define
MAX 500
void
main()
{
FILE
*fp;
int
std_no[MAX],marks[MAX];
char
name[MAX] [20];
int
i,n;
printf("How
many data?");
scanf("%d",&n);
fp=fopen("record.dat","w+");
for(i=0;i<n;++i)
{
printf("Enter
roll number:");
scanf("%d",&std_no[i]);
fflush(stdin);
printf("Enter
name");
scanf("%s",name[i]);
print("Enter
marks:");
scanf("%d",&marks[i]);
fprint(fp,
"%d%s%d", std_no[i],marks[i]);
}
rewind
(fp);
printf("Roll
number/tName/tMarks/n");
printf("------------------------/n");
for(i=0;i<n;++i)
{
fscanf(fp,
"%d%s%d",&std_no[i],name[i],&marks[i]);
printf("%d/r%s/t%d/n",std_no[i],name[i]marks[i]);
}
fclose(fp);
getch();
}
5.
Write a c program using C language
that reads successive records from the new data file and display each record on
the screen in an appropriate format.
#include<stdio.h>
#include<conio.h>
struct student
{
char name[30];
int roll,age;
}s;
void main()
{
FILE *ptr;
char choice;
clrscr();
ptr=fopen("record.txt","w");
do
{
printf("\n Input
name:-");
gets(s.name);
printf("\n Input roll number
and age:-");
scanf("%d%d",&s.roll,&s.age);
fwrite(&s,sizeof(s),1,ptr);
fflush(stdin);
printf("\n Any more
record:-");
choice==getche();
}while(choice=='y'||choice=='Y');
fclose(ptr);
ptr=fopen("record.txt","r");
printf("\n Name \t Roll \t
Age");
while(fread(&S,sizeof(s),1,ptr)==1)
printf("\n %s \t %d \t
%d",s.name,s.roll,s.age);
fclose(ptr);
getch();
}
6. Write a
c program to rename and delete a data file using rename and remove command.
#include<stdio.h>
#include<conio.h>
#include<string.h>
struct student
{int roll;
char name[30];
}s;
void main() {
char temp_name[30];
FILE *ptr1;
FILE *ptr2;
clrscr();
ptr1=fopen("student.txt","r");
ptr2=fopen("temp.txt","w");
printf("\n Input name to deleted:-");
gets(temp_name);
while(fscanf(ptr1,"%d%s",&s.roll,s.name)!=EOF)
{
if(strcmp(temp_name,s.name)==0)
fprintf(ptr2,"%d\t%s",s.roll,s.name);
}
fclose(ptr1);
remove("student.txt");
rename("temp.txt","student.txt");
fclose(ptr2);
getch();
}
7. Write a
c program to open a new file and read roll-no, name, address and phone number
of students until the user says “no”, after reading the data, write it to the
fie then display the content of the file.
#include<stdio.h>
#include<conio.h>
struct student
{
char name[30],address[50];
int roll;
long int phone;
}s;
void main() {
FILE *ptr;
char choice;
clrscr();
ptr=fopen("record.txt","w");
do
{
printf("\n
Input Name:-");
gets(s.name);
printf("\n input address");
gets(s.address);
printf("\n Input roll number and phone
number:-");
scanf("%d%1d",&s.roll,s.phone);
fwrite(&s,sizeof(s),1,ptr);
fflush(stdin);
printf("\n Any more record:- ");
choice==getche();
}
while(choice=='y'||choice=='Y');
fclose(ptr);
ptr=fopen("record.txt","r");
printf("\n Name \t Address \t Roll \t Phone");
while(fread(&s,sizeof(s),1,ptr)==1)
printf("\n%s \t %s \t %d \t
%1d",s.name,s.address,s.roll,s.phone);
fclose(ptr);
getch();
}
8. Write a
c program which asks name, age, roll number of student and write it in a file
student.dat.
#include
<stdio.h>
#include
<conio.h>
void
main ()
{
char
name [30], add [20],
long
int phone;
FILE
*fp;
fp =
fopen ("STUD.DAT", "w+");
for
(I = 0; i<5; i++)
{
printf
("Enter anme : /n");
scanf
("%s", name [i]);
printf
("Enter address : /n");
scanf
("%s", add [i]);
printf
("Enter phone : /n");
scanf
("%ld", &phone [i]);
fprintf
(fp, "%s%s%d", name[i],phone[i]);
}
rewind
(fp); //Sets the file pointer at the beginning of a file
for
(I = 0; i<5; i++)
{
fscanf
(fp, "%s %s %ld', name, add, &phone);
printf
("Name = %s /t Address = %s /t phone = % /d", name [i], add [i],
phone [i];
}
fclose
(fp);
getch
();
}
v 17. Write
an algorithm, flowchart, and C program that checks whether the number entered
by the user is exactly divisible by 5 but not by 11.
#include<stdio.h>
#include<conio.h>
void main()
{
int num;
clrscr();
printf("\n Input a number:-");
scanf("%d",&num);
if(num%5==0&&num%11!=0)
printf("\n The number %d is exactly divisible by 5
but not by 11",num);
else
printf
printf("\n The number %d is not required
number",num);
getch();
}
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