How to Print

beginner c++11

In C++ printing is done with the std::cout object and the left shift operator (<<).

#include <iostream>

int main() {
    std::cout << "Hello, World!\n";
}

Hello, World!

You can chain multiple objects together of different types:

#include <iostream>

int main() {
    std::cout << "Mars is " << 1.5 << "AU from the Sun.\n";
}

Mars is 1.5AU from the Sun.

Printing Custom Types

By default, C++ will not know how to print the types you define. To tell C++ how to print your types you overload the left shift operator(<<) of std::ostream.

#include <iostream>

struct Point {
    float x, y, z;
};

std::ostream& operator<<(std::ostream& o, const Point& p) {
    o << p.x << ", " << p.y << ", " << p.z;
    return o;
}

int main() {
    Point p{1.0f, 2.0f, 3.0f};
    std::cout << p << "\n";
}

1, 2, 3

Just print()

It’s possible to have a more comfortable to use print function in C++. Click here to see how.

Priting std Containers

C++’s standard library containers do not come with printing capability. In order to print a std::vector or a std::map we need to write our own printing function. Click here to see how.