C program to find factorial of a number|in 7 ways

C program to find factorial of a number|in 7 ways

In this tutorial, we will discuss the C program to find factorial of a number|in 7 ways

In this post, we are going to learn how to find the factorial of a number or the given number in C language

What is the factorial of a number (n)?

The factorial of a number (n) is the product of all positive integers from 1 up to n (n is the given number).

It is simply denoted by n!.

Example

if you want to find the factorial of number 5, you can follow this method.
Factorial of 5 will be 5*4*3*2*1=120
So, 5!=120.

Program 1

Find factorial of a number – using stranded method

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int i,num=5,fact=1;
    for(i=1; i<=num; i++)
    {
        fact=fact*i;
    }
    printf("Factorial of %d is: %d",num,fact);
    getch();
    return 0;
}

When the above code is executed it produces the following output

Factorial of 5 is: 120

In this program

1. Integer variable i, num1,fact are declared and initialized
2. the program finds the factorial using for loop
3. Then, the program is displayed the factorial of a number using println() function
   

Program 2

Find factorial of a number – using for loop

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int i,num,fact=1;
    printf("Enter the number for find factorial: ");
    scanf("%d",&num);
    for(i=1; i<=num; i++)
    {
        fact=fact*i;
    }
    printf("Factorial of %d is: %d",num,fact);
    getch();

    return 0;
}

When the above code is executed it produces the following output

Enter the number for find factorial: 4
Factorial of 4 is: 24

The program allows the user to enter a value and it finds and displays factorial of the given number using for loop in C language

Program 3

Find factorial of a number – using while loop

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int num,fact=1;
    printf("Enter the number for find factorial\n");
    scanf("%d",&num);
    int i=1;
    while(i<=num){
        fact=fact*i;
        i++;
    }
    printf("Factorial of %d is : %d",num,fact);
    getch();
    return 0;
}

When the above code is executed it produces the following output

Enter the number for find factorial
7
factorial of 7 is:5080

The program allows the user to enter a value and it finds and displays factorial of the given number using while loop in C language

Program 4

Find factorial of a number – using do-while loop

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int num,fact=1;
    printf("Enter the number to find factorial\n");
    scanf("%d",&num);
    int i=1;
  do{
        fact=fact*i;
        i++;
    }  while(i<=num);
    printf("Factorial of %d is : %d",num,fact);
    getch();
    return 0;
}

When the above code is executed it produces the following output

Enter the number to find fatorial
4
Factorial of 4 is : 24

The program allows the user to enter a value and it finds and displays factorial of the given number using the do-while loop in C language

Program 5

Find factorial of a number – using function

#include <stdio.h>
#include <stdlib.h>

int main()
{

    printf("Enter the number for find factorial\n");
fact();  //function call

}
  int fact(){  //function definition
       int i,num,fact=1;
        scanf("%d",&num);
        i=1;
while(i<=num){
    fact=fact*i;
    i++;
    }
    printf("Factorial of %d is : %d",num,fact);
//Display factorial
    getch();
    return 0;
}

When the above code is executed it produces the following output

Enter the number for find factorial
6
factorial of 6 is: 720

The program allows the user to enter a value and it finds and displays factorial of the given number using the function in C language

Program 6

Find factorial of a number – using recursion

#include <stdio.h>
#include <stdlib.h>
long int findFact(int num);
int main()
{
    int num;
    printf("Enter a positive integer: ");
    scanf("%d",&num);
    printf("factorial of %d = %ld",num,findFact(num));
getch();
    return 0;
}
long int findFact(int num){
if (num>=1)
    return num*findFact(num-1);
else
    return 1;

}

When the above code is executed it produces the following output

Enter a positive integer: 8
factorial of  8 = 40320

The program allows the user to enter a value and it finds and displays factorial of the given number using recursion in C language

Program 7

Find factorial of a number – using the pointer

#include <stdio.h>
#include <stdlib.h>
void Factorial(int, long int*);
int main()
{
    long int fact;
    int num;

    printf("Enter a integer to find factorial\n");
    scanf("%d",&num);
    Factorial(num,&fact);
    printf("factorial of %d is %d ",num,fact);
    getch();
    return 0;
}
void Factorial(int n, long int *fact){
int i;

*fact=1;
for(i=1; i<=n; i++)
    *fact=*fact*i;

}

When the above code is executed it produces the following output

Enter a integerto find factorial
5
factorial of 5 is 120

The program allows the user to enter a value and it finds and displays factorial of the given number using the pointer in C language

 

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