for Loop

Purpose:

To repeat a block of code a predetermined number of times.

Mechanics:

for (<counter initialization>; <loop continuation condition>; <counter increment>) {
/* Java statements */
}

Example:

for (int i=0; i<10; i++) {
/* Java statements */
}

Usage:

  • <counter initialization> is a variable of an ordinal type, such as an integer initialized to a value.
  • The <loop continuation condition> determines how long the program will continue to loop.
  • <counter increment> increments the counter using an increment operator, usually <counter>++.
  • The /* Java statements */ can be any legal Java statements. If more than one statement is to be repeated, then curly brackets must surround the repeated code. Otherwise, the curly brackets are optional.

Restrictions:

  • When the for structure begins executing, the counter is initialized. Then, the <loop continuation condition> is checked. If the condition is satisfied, the /* Java statements */ are executed, and then the counter is incremented. The loop begins again by checking the <loop continuation condition>. This process continues until the control variable no longer satisfies the <loop continuation condition>. The program continues by performing the first statement after the for structure.
  • The value of <counter> can be used in a expression but cannot be changed with an assignment statement in the body of the loop.
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