=>>What is the difference between '#define' and 'const int (global)' in C++ ?

Question

#define PI 3.14

const float PI 3.14

What is the difference between these two ??

Answer 1

#define is a preprocessor directive/macro that will replace every "PI" in your code with 3.14 before it is compiled. So by the time the code is compiled, there is no variable/constant "PI" in your code anymore and the compiler has no idea what "PI" is. All it "sees" is 3.14.

const float on the other hand defines a constant. It's like a regular variable, but it can't be changed.