What is the meaning of header, pre processor, compiler in C++ programming

Question

1st example in basic concept of C++ language

Answer 1

Typically headers contain one or more of the following:

Function declaration (except statics)
Variable declaration (typically global)
User defined type declaration (read struct, union etc.)
Macro definition

Pre processor are some pre define term starting with # like include and define.

Compiler use to compiler means change your code to machine language and show you the output that generated.

Answer 2

Pre processor process the code before the compiler reads it. It "copies" the text of the included header files (which contain usually classes and function declarations you're about to use) into the file. It also removes comments because the compiler can't do anything with them. Prepocessor commands exist that ensure that files are included only once and not multiple times. After that the compiler is used to link files and translate the code into a language the computer understands (machine code, binary digits), the compiler also looks for errors in the code.