Practical-03

Write a program to find factorial of given no using recursion.

Introduction

In this program, we will learn to write a recursive function to calculate the factorial of a given number.

Algorithm

1. Start
2. Declare variables number and result.
3. Take input from user and store it in number.
4. Call the factorial function to calculate the factorial of the given number.
5. Print the factorial of the given number.
6. End

Code

Practical-03.c

#include<stdio.h>

int factorial(int number); // declare the prototype of factorial function

void main(){
  int number;

  printf("Enter an integer: "); // prompt user to enter an integer
  scanf("%d", &number); // read the input and store in the variable number

  int result = factorial(number); // call the factorial function to calculate factorial

  printf("The factorial of %d is %d\n", number, result); // print the result

}

int factorial(int number){
    if(number == 0) // base case
       return 1; // factorial of 0 is 1
    else
       return number * factorial(number - 1); // recursive call
}

Output

Enter an integer: 5
The factorial of 5 is 120

Explanation

The program first asks the user to enter an integer. Then it calls the factorial function to calculate the factorial of the given number. The factorial function is a recursive function. It calls itself until the base case is reached. The base case is when the number is 0. The factorial of 0 is 1. The factorial function returns the factorial of the given number.