How to read the entire value of a double using cin?

Question

long double m;
cout << \"enter double: \"; cin >> m;
cout << \"m = \" << m <

Input:

enter double: 1.546

Answer 1

You have read the whole value of the double. The problem is with the cout. It by default rounds the value to 6 digits after the decimal point.

To set the precision cout uses, use setprecision from <iomanip>:

#include <iostream>
#include <iomanip>

using namespace std;

int main() {
    long double d;
    cin >> d;
    cout << setprecision(10) << d << endl;
    return 0;
}