c program to find factorial of 100 or very large numbers Given by User In C

c program to find factorial of 100 or very large numbers Given by User in C

#include
#define MAX 10000
void factorialof(int);
void multiply(int);
int length = 0;
int fact[MAX];

int main(){
    int num;
    int i;

    printf("Enter any integer number : ");
    scanf("%d",&num);
   
    fact[0]=1;

    factorialof(num);
   
    printf("Factorial is : ");
    for(i=length;i>=0;i--)
    {
         printf("%d",fact[i]);
    }
    return 0;
}
void factorialof(int num)
{
    int i;
    for(i=2;i<=num;i++)
{
         multiply(i);
    }
}
void multiply(int num)
{
    long i,r=0;
    int arr[MAX];
    for(i=0;i<=length;i++)
       {
                arr[i]=fact[i];
        }

    for(i=0;i<=length;i++){
         fact[i] = (arr[i]*num + r)%10;
         r = (arr[i]*num + r)/10;
         //printf("%d ",r);
    }
    if(r!=0){
         while(r!=0){
             fact[i]=r%10;
             r= r/10;
             i++;
         }
    }
    length = i-1;   
}