Show more accuracy in C++

Question

I have this program:

int main(){
    double x=2;
    cout << sqrt(x);
}

I would like to show the result as accurately as possible. Thank you!

Answer 1

Utilizes setprecision in this way:

#include <iostream>
#include <cmath>
#include <iomanip>
#include <limits>           // Para ter a máxima precisão

using namespace std;

int main(){
    double x=2;
    cout << setprecision(numeric_limits<double>::max_digits10) << sqrt(x);
}

Answer 2

You can do it like this:

#include <iostream>
#include <cmath>
using namespace std;

int main() {
    double num = sqrt(2);
    cout << fixed;
    cout.precision(52);
    cout << num << endl;
}

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