Program 1: Factorial program in c using for loop

#include<stdio.h>
int main(){
  int i,f=1,num;

  printf("Enter a number: ");
  scanf("%d",&num);

  for(i=1;i<=num;i++)
      f=f*i;

  printf("Factorial of %d is: %d",num,f);
  return 0;
}

Result

Enter a number: 8
Factorial of 8 is: 40320

Program 2: Factorial program in c using pointers

#include<stdio.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;
}

Result

Enter a number: 8
Factorial of 8 is: 40320

Program 3: Factorial program in c using function

#include<stdio.h>

int findFactorial(int);
int main(){
  int i,factorial,num;

  printf("Enter a number: ");
  scanf("%d",&num);

  factorial = findFactorial(num);
  printf("Factorial of %d is: %d",num,factorial);

  return 0;
}

int findFactorial(int num){
    int i,f=1;

    for(i=1;i<=num;i++)
      f=f*i;

     return f;
}

Result

Enter a number: 8
Factorial of 8 is: 40320

Program 4: Factorial series in c

#include<stdio.h>
int main(){
  long f=1;
  int i,num,min,max;

  printf("Enter the minimum range: ");
  scanf("%d",&min);

  printf("Enter the maximum range: ");
  scanf("%d",&max);

  printf("Factorial series in given range: ");
  for(num=min;num<=max;num++){
    f=1;

    for(i=1;i<=num;i++)
      f=f*i;

    printf("%ld ",f);
  }

  return 0;
}

Result

Enter the minimum range: 1
Enter the maximum range: 10
Factorial series in given range: 1 2 6 24 120 720 5040 40320 362880 

Program 5: Factorial program in c without using recursion

#include<stdio.h>
int main(){
  int i=1,f=1,num;

  printf("Enter a number: ");
  scanf("%d",&num);

  while(i<=num){
      f=f*i;
      i++;
  }

  printf("Factorial of %d is: %d",num,f);
  return 0;
}

Result

Enter a number: 5
Factorial of 5 is: 120