To add - the preprocessor is a pretty dated thing that merely uses text substitution, so you have no easy way to debug the code that the preprocessor passes to the compiler. Defines such as function-like macros throw away type safety and can have extremely unexpected behavior. For example, you might think this code will do what you want.

#define SQ(x) x*x

cout << SQ(2) // prints 4 since 2*2 = 4

cout << SQ(1+3) // prints 7 since 1+3*1+3 = 7

Macros are pretty much entirely unnecessary and should be avoided. Compilers inline nowadays, so you don’t really gain anything from using a macro when you could have just made a function that gives you type safety and intuitive behavior. If you are trying to define constants, use const, enum, or enum classes. If you are trying to define multiple versions of the same function, use polymorphism or templates. If you are trying to wrap around arbitrary code, use lambdas.