Summary of the The C Preprocessor in C programming language

(a) The preprocessor directives enable the programmer to write programs that are easy to develop, read, modify and transport to a different computer system

(b)We can make use of various preprocessor directives such as #define, #include, #ifdef - #else - #endif, #if and #elif in our program.

(c)The directives like #undef and #pragma are also useful although they are seldom used.