cpp define

Define and Explain a C++ define Directive

#define PI 3.14159

• The define directive is used in C++ to create symbolic constants.
• In this example, PI is being defined as a symbolic constant with the value 3.14159.
• Whenever the program encounters PI in the code, it will be replaced with 3.14159 during the preprocessing stage.
• This allows for easy modification of the value at a single location in the code, which will be reflected wherever PI is used.
• It's important to note that define is a preprocessor directive, meaning it operates before the code is compiled, and it does not respect the scope of variables like regular C++ constants.