Global and local variables

A local variable is a variable that is declared inside a function. A global variable is a variable that is declared outside all functions. A local variable can only be used in the function where it is declared. A global variable can be used in all functions.

See the following example:

 #include<stdio.h>

 // Global variables
 int A;
 int B;

 int Add()
 {
  return A + B;
 }

 int main()
 {
  int answer; // Local variable
  A = 5;
  B = 7;
  answer = Add();
  printf("%d\n",answer);
  return 0;
 }

As you can see two global variables are declared, A and B. These variables can be used in main() and Add().
The local variable answer can only be used in main().

That’s all for this tutorial.