Problems with uint64_t in C++

Question

I have a problem with very large numbers. When I put the input 64 my program does not display the right answer, remembering that all smaller numbers are with normal output.

Exit from the program:

0 kg

Expected exit:

1537228672809129 kg

source code:

#include <iostream>    
using namespace std;



int main(){

    int a;
    uint64_t x=1,kg;
    cin>>a;
    for(int cont=0;cont<a;cont++){
        x*=2.0;
    }
    kg=x/12/1000;
    cout<<kg<<" kg\n";




}

Answer 1

You’ll have to use a library BigInteger or create one of their own. Each has its advantages and disadvantages. I have chosen the Infint by being simple to pick up and use, but it does not have a function or exponentiation operator, which could eliminate this loop. But at least it works:

int a;
cin >> a;
InfInt x = 1, kg;
for (int cont = 0; cont < a; cont++) {
    x *= 2;
}
kg = x / 12000;
cout << kg << " kg\n";

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.