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4) Factorial

Factorial of n is the product of all positive descending integers. Factorial of n is denoted by n!.

There are many ways to write the factorial program in c language. Let's see the 2 ways to write the factorial program.

  • Factorial Program using loop

  • Factorial Program using recursion

Write a c program to print factorial of a number.

Input: 5

Output: 120

Input: 6

Output: 720

Factorial Program using loop

Let's see the factorial Program using loop.

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#include<stdio.h>  

int main()    

{    

 int i,fact=1,number;    

 printf("Enter a number: ");    

  scanf("%d",&number);    

    for(i=1;i<=number;i++){    

      fact=fact*i;    

  }    

  printf("Factorial of %d is: %d",number,fact);    

return 0;  

}   

Factorial Program using recursion in C

Let's see the factorial program in c using recursion.

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#include<stdio.h>  

  

long factorial(int n)  

{  

  if (n == 0)  

    return 1;  

  else  

    return(n * factorial(n-1));  

}  

   

void main()  

{  

  int number;  

  long fact;  

  printf("Enter a number: ");  

  scanf("%d", &number);   

   

  fact = factorial(number);  

  printf("Factorial of %d is %ld\n", number, fact);  

  return 0;  

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