Local variables – Coding Friends

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.

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