Write a C program to define, undefine and redefine a macro (compile time constant). How to define, remove and redefine a macro in C programming. How to define, remove and redefine a compile time constant (macro) in C programming.
ifdef
C preprocessor directives – #include, #define, #undef and conditional directives
A C preprocessor is a statement substitution (text substitution) in C programming language. It instructs the C compiler to do some specific (required) pre-processing before the compilation process.
When we compile a C program, C preprocessor processes the statements which are associated with it and expand them to make the code for further compilation.