This is a tutorial about variable scope, a variable is a means to store data within the context of the program. For example, if you wish to store a numerical value then you would not store that number in a string, but within a integer or floating point number.
There are different types of variables, integer / string etc, but the scope of a variable is the area in which the variable is defined within block of code that it is situated.
This is some c++ code to demonstrate the difference between local variables and global.
#include <iostream> // global variable int value1 = 0; void globalVariable() { // output the global variable std::cout << "Global " << value1 << "\n"; } int main(void) { int value1 = 1; // local function variable globalVariable(); // output the global std::cout << "Local " << value1 << "\n"; // output the local // the value1 here is local to the for loop for (int value1 = 10; value1 < 15; value1++) { std::cout << "For loop : " << value1 << "\n"; } // output the global and local and notice they have not changed with the very local for loop // with the same variable name. globalVariable(); std::cout << "Local " << value1 << "\n"; return 0; } |
the output would be
Global 0 Local 1 For loop : 10 For loop : 11 For loop : 12 For loop : 13 For loop : 14 Global 0 Local 1
To demonstrate that the global /local and looping locals do only work within there area.