Illustrate variable scoping - C++ Language Basics

C++ examples for Language Basics:Variable

  1. HOME
  2. C++
  3. Language Basics
  4. Variable

Description

Illustrate variable scoping

Demo Code

#include <iostream>

void useLocal();/* w ww.  ja  va 2  s  . co  m*/
void useStaticLocal();
void useGlobal();

int x = 1;

int main(int argc, const char *argv[]) {
    std::cout << "global x in main is " << x << std::endl;

    int x = 5;

    std::cout << "local x in main's outer scope is " << x << std::endl;

    {
        std::cout << "start new scope " << std::endl;
        
        int x = 7;  // hides both x in outer scope and global x

        std::cout << "local x in main's inner scope is " << x << std::endl;
    }

    std::cout << "local x in main's outer scope is " << x << std::endl;

    useLocal();
    useStaticLocal();
    useGlobal();
    useLocal();
    useStaticLocal();
    useGlobal();

    std::cout << "\nlocal x in main is " << x << std::endl;
    return 0;
}
void useLocal() {
    int x = 25;

    std::cout << "\nlocal x is " << x << " on entering useLocal" << std::endl;
    ++x;
    std::cout << "local x is " << x << " on exiting useLocal" << std::endl;
}
void useStaticLocal() {
    static int x = 50;

    std::cout << "\nlocal static x is " << x << " on entering useStaticLocal"
              << std::endl;

    ++x;

    std::cout << "local static x is " << x << " on exiting useStaticLocal"
              << std::endl;
}
void useGlobal() {
    std::cout << "\nglobal x is " << x << " on entering useGlobal" << std::endl;

    x *= 10;

    std::cout << "global x is " << x << " on exiting useGlobal" << std::endl;
}

Result


Related Tutorials