Why testcase 1 showing run error

#1

#include
using namespace std;

#define MAX 500

int multiply(int x, int res[], int res_size);

void factorial(int n)
{
int res[MAX];

res[0] = 1; 
int res_size = 1;  
for (int x=2; x<=n; x++) 
	res_size = multiply(x, res, res_size); 


for (int i=res_size-1; i>=0; i--) 
	cout << res[i];

}

int multiply(int x, int res[], int res_size)
{
int carry = 0;
for (int i=0; i<res_size; i++)
{
int prod = res[i] * x + carry;

	res[i] = prod % 10; 

	carry = prod/10;	 
} 

while (carry) 
{ 
	res[res_size] = carry%10; 
	carry = carry/10; 
	res_size++; 
} 
return res_size;

}

int main()
{
int n;
cin>>n;
factorial(n);
return 0;
}

#2

Pls change the size as : #define MAX 1000 and then try to submit your code…