C++

7.3    Using Functions

Before we delve further into how to write functions yourself, let's first look at their usage.

// https://godbolt.org/z/TdrebYodx#include <iostream>                     // cout#include <cmath>                        // sin#include <string>#include <vector>using std::sin;int main() {    std::cout << "sin(0.0): " << sin(0.0) << "\n";       // call sin() with literal    double angle = 3.1415/2;    std::cout << "sin("<<angle<<"): "<<sin(angle)<<"\n"; // call with variable    std::string name = "Han Solo";    std::cout << name.length() << "\n"; // call a method                                        // ... conceptually like length(name)    std::vector<int> data{};    data.push_back(5);                  // further method call with parameter    data.push_back(10);    std::cout << data.back() << " ";    data.pop_back();    std::cout << data.back() << "\n"; data. ...