Factorial of a Number using Recursion

In this example, We will learn a program to Factorial of a Number using Recursion. Before that, You must have knowledge of the following topics.

• For Loop
• Recursive Function

Make sure you have knowledge of Recursive Function.

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Now, we will look on algorithm and flowchart and we will write flowchart of plain program. i.e without using recursive function.

We can also find the factorial without using recursive function or any functions. Below is the code

#include<stdio.h>

int main(){
    
    int num, fact=1, i;
    printf("Enter a number: ");
    scanf("%d", &num);

    for( i = num; i > 0; i-- ){
        fact *= i;
    }
    printf("\nFactorial of  %d is  %d", num, fact);
    return 0;

}

Algorithm

The algorithm of above program is

Step 1: Start
Step 2: Declare Variable n, fact, i
Step 3: Read number from User
Step 4: Initialize Variable fact=1 and i=num
Step 5: Repeat Until i > 0
            fact=fact*i
            Decrease i by 1
Step 6: Print fact
Step 7: Stop

Flowchart

This is the flowchart of this program

CODE: Factorial of a Number using Recursion

Now, We will learn a code to find Factorial of a any Number using Recursion.

#include<stdio.h>

//Function Prototype
int fact(int);

int main(){
    
    int num;
    printf("Enter a number: ");
    scanf("%d", &num);
    printf("\nFactorial of  %d is  %d", num, fact(num));
    return 0;

}

int fact(int a){

    if( a == 1 || a == 0 )
        return 1;
    else
        return ( a * fact( a - 1 ) );
        
}

The output of above program is

Enter a number: 5
Factorial of  5 is  120