C++

7.5    More about Parameters

In C++, the declaration of the parameter in the function header determines how the parameter behaves when called. The most important distinction is whether the parameter is passed as a value or as a reference.

7.5.1    Call-by-Value

If you do not take any special precautions, the parameters of a function in C++ are passed as values (call-by-value). This means that if a variable x currently has the value 5 and you pass x to a function, then the 5 ends up in the function—not the x.

// https://godbolt.org/z/8zcvMdM3b#include <iostream>void print_val8(int n) {           // parameter as value    std::cout << n << " ";    n = 8;                         // sets parameter to 8    std::cout << n << "\n";}int main() {    int x = 5;    print_val8(x);                 // x as value: prints ...