for

for

A for loop performs initialization before the first iteration. Then it performs conditional testing and, at the end of each iteration, some form of "stepping." The form of the for loop is:

for(initialization  Boolean-expression; step)
statement

Any of the expressions initialization, Boolean-expression or step can be empty. The expression is tested before each iteration, and as soon as it evaluates to false execution will continue at the line following the for statement. At the end of each loop, the step executes.

for loops are usually used for "counting" tasks:

Note that the variable c is defined at the point where it is used, inside the control expression of the for loop, rather than at the beginning of the block denoted by the open curly brace. The scope of c is the expression controlled by the for.

Traditional procedural languages like C require that all variables be defined at the beginning of a block so when the compiler creates a block it can allocate space for those variables. In Java and C++ you can spread your variable declarations throughout the block, defining them at the point that you need them. This allows a more natural coding style and makes code easier to understand.

You can define multiple variables within a for statement, but they must be of the same type:

The int definition in the for statement covers both i and j. The ability to define variables in the control expression is limited to the for loop. You cannot use this approach with any of the other selection or iteration statements.