C++

13.7    “static” Makes Permanent

Similar, but not the same, is the use of static with local variables—that is, within a function. When you add static to the declaration of a local variable, this variable persists when the program flow leaves the scope and is reused when it is entered again.

// https://godbolt.org/z/h5qond6db#include <iostream>                     // coutclass Keyboard {    Keyboard(const Keyboard&) = delete; // no copy    const size_t nr_;                   // current numberpublic:    static inline size_t count_ = 0;    // counts created instances    explicit Keyboard() : nr_{count_++} {        std::cout << "  Keyboard().nr:"<<nr_<<"\n";    }};Keyboard& getKeyboard() {    std::cout << "  getKeyboard()\n";    static Keyboard keyboard{};         // static local variable    return keyboard;}void func() { std::cout ...