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for (C# Reference)

The for loop executes a statement or a block of statements repeatedly until a specified expression evaluates to false. The for loop is useful for iterating over arrays and for sequential processing.

In the following example, the value of int i is written to the console and i is incremented every time through the loop by 1.

class ForLoopTest 
    static void Main() 
        for (int i = 1; i <= 5; i++)

The for statement executes the enclosed statement or statements repeatedly as follows:

  • First, the initial value of the variable i is evaluated.

  • Then, as long as the value of i is less than or equal to 5, the condition evaluates to true, the Console.WriteLine statement is executed and i is reevaluated.

  • When i is greater than 5, the condition becomes false and control is transferred outside the loop.

Because the test of a conditional expression occurs before the execution of the loop, a for statement executes zero or more times.

All of the expressions of the for statement are optional; for example, the following statement is used to write an infinite loop:

for (; ; )
    // ...

For more information, see the following sections in the C# Language Specification:

  • For statements

  • 8.8.3 The for statement