Iteration statements cause statements (or compound statements) to be executed zero or more times, subject to some loop-termination criteria. When these statements are compound statements, they are executed in order, except when either the break statement or the continue statement is encountered. (For a description of these statements, see The break Statement and The continue Statement.)
C++ provides three iteration statements — while, do, and for. Each of these iterates until its termination expression evaluates to zero (false), or until loop termination is forced with a break statement. Table 5.2 summarizes these statements and their actions; each is discussed in detail in the sections that follow.
Table 5.2 C++ Iteration Statements
| Statement | Evaluated At | Initialization | Increment |
| while | Top of loop | No | No |
| do | Bottom of loop | No | No |
| for | Top of loop | Yes | Yes |
Syntax
iteration-statement :
while ( expression ) statement
do statement while ( expression ) ;
for ( for-init-statement expressionopt ; expressionopt ) statement
for-init-statement :
expression-statement
declaration-statement
The statement part of an iteration statement cannot be a declaration. However, it can be a compound statement containing a declaration.