C++ Primer, Fifth Edition

5.4.2. Traditional for Statement

The syntactic form of the for statement is:

for (init-statement condition; expression)    statement

The for and the part inside the parentheses is often referred to as the for header.

init-statement must be a declaration statement, an expression statement, or a null statement. Each of these statements ends with a semicolon, so the syntactic form can also be thought of as

for (initializer; condition; expression)      statement

In general, init-statement is used to initialize or assign a starting value that is modified over the course of the loop. condition serves as the loop control. As long as condition evaluates ...