There are two versions of the for statement, iteration and range-based. The latter was introduced in C++11. The iteration version has the following format:
for (init_expression; condition; loop_expression) loop_statement;
You can provide one or more loop statements, and for more than one statement, you should provide a code block using braces. The purpose of the loop may be served by the loop expression, in which case you may not want a loop statement to be executed; here, you use the null statement, ; which means do nothing.
Within the parentheses are three expressions separated by semicolons. The first expression allows you to declare and initialize a loop variable. This variable is scoped to the for statement, ...