Define Keywords in C++
Keywords are the words already used by C++ in its compiler. They are also known as reserved words, because these words are completely defined for C++ interpretation. Therefore keywords cannot be used to declare any identifiers in the program. Some of the example of keywords are, if, else, for, operator, while, cout, void, class, cin, inline, friend, etc. Therefore a program will not compile with keyword as identifier.
int if; This is an wrong statement because a variable name or identifier cannot have keyword if as the variable.