A variable declaration serves three purposes:
It defines the name of the variable.
It defines the type of the variable (integer, real, character, etc.).
It gives the programmer a description of the variable.
int answer; /* the result of our expression */
The keyword int tells C that this variable contains an integer value.
The variable name is answer.
The semicolon (;) marks the end of the statement.
The comment is used to define this variable for the programmer.