Efficient Program for Factorial using Memoization

#include <iostream>

using namespace std;

long long int cache[100000]={0};

long long int fact(long long int n)

{

if(n<=1)

return 1;

else 
    if(cache[n]>0)

return cache[n];

else

{

        long long int v=n*fact(n-1);

cache[n]=v;

return v;

}

}

int main()

 {

    long long int n;

   cin>>n;

   cout<<"Factorial of  "<<n <<"is = "<<fact(n);

   return 0;

}