Factorization of large numbers ← C language

【 Algorithm code 】

#include<stdio.h>
#define maxn 10005

int a[maxn]={1};
int len=maxn;
int c=0;

int main() {	
	int n;
	scanf("%d",&n);
	
	int i,j;
	for(i=2; i<=n; i++)
		for(c=0,j=0; j<len; j++) {
			a[j]=a[j]*i+c;
			c=a[j]/10;
			a[j]%=10;
		}

	for(i=len-1; a[i]==0; i--); //Get rid of the leading zero
	
	for(j=i; j>=0; j--)
		printf("%d",a[j]);

	return  0;
}


/*
20
2432902008176640000
*/

【 reference 】
https://blog.csdn.net/lisp1995/article/details/52403507
https://www.csdn.net/tags/NtDaMg4sODU4ODktYmxvZwO0O0OO0O0O.html