How to output with 3 digits after the decimal point with C++ stream?

Question

Given a variable of float type, how to output it with 3 digits after the decimal point, using iostream in C++?

Answer 1

This one does show "13.141"

#include 
#include 
using namespace std;

int main(){
    double f = 13.14159;
    cout << fixed;
    cout << setprecision(3) << f << endl;
    return 0;
}