Display number with decimal places instead of whole number

Question

I have this

double a = 4.0;
double b = 2.0;
double g = a + b;

std::cout << g;

I am getting 6, but I want to get 6.0

Answer 1

If you always want one figure after the decimal point regardless of how many digits the answer is, use std::fixed along with std::setprecision

#include <iomanip>

std::cout << std::fixed << std::setprecision(1) << g;

Answer 2

One way:

#include <iomanip>
//...
std::cout << std::setprecision(2) << g;

This sets the precision of the output to 2 significant figures.

Edit: as the other answer points out, prepend std::setprecision with std::fixed.