What is the difference between macros and constant variable?

Answer 1

Macros are processed at preprocessing time where as constant variables are processed at complie time. Macros doesnot have any scope but constant variables has scope. Macros doesnot have the type checking where as constant variables have type checking.

Answer 2

program veriable is a simple veriable of any program its value can be change or modify in future but if we have any constant in our program we cannot change its value we can only use it in increment & decrement and contatant value(fixed value)

e.g : if we have two variable a and b a is constant and b is simple variable

we can use like that:

constant int a=10;

int b=20;

we can change b's value like b=30;

Not like that a=20; its will give error in you program

we can increment or decrement it like a++;a--;

not have other difference b/w them