Broken Calculator Question problem

#1

my program is correct but it gives 0 output to 100!
//Broken calculator
#include
using namespace std;
int main(){

unsigned long long int f=1,i,n;
cin>>n;
for(i=1;i<=n;++i){
f=f*i;
}
cout<<f;
}

#2

@dsingh200021
100 ! is a large number , 157 digits large. long long int can only store a number as long as 18 digits. There is no other predefined data type that can store a number that large. And that is what the question is all about. You need to find your way around this. Construct your own data type (sort of) to store such a large number and do calculations on it.
Computing factorial is not a big task , storing such a large number is .