for

for (FOR-INIT ; EXPRESSION ; STATEMENT-EXPRESSION , STATEMENT-EXPRESSION ...) STATEMENT
This form first evaluates the FOR-INIT. Then it evaluates the expression, which must have type boolean. If the expression evaluates to true, the STATEMENT is evaluated. At the completion of the STATEMENT, the STATEMENT-EXPRESSIONs are evaluated, and then the expression is evaluated again. If the expression evaluates to false, then the for statement has completed without executing the STATEMENT-EXPRESSIONs or the STATEMENT.
for( ; ; )STATEMENT
This form will continuously evaluate the statement (and reevaluate it) unless something internally ceases the execution. The two for constructs can be mixed, so that any one spot is empty.