C# for loop

The for loop executes a statement or a block of statements repeatedly until a specified expression evaluates to false. The for loop is handy 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 each time through the loop by 1.

Example:

// statements_for.cs
// for loop
using System;
class ForLoopTest 
{
    static void Main() 
    {
        for (int i = 1; i <= 5; i++)
        {
            Console.WriteLine(i);
        }
    }
}

Output: 

1 

2 

3 

4 

5

Remarks:

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

• First, the initial value of the variable i is evaluated.
• Then, while 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 conditional expression takes place before the execution of the loop, therefore, 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 (;;)
{
    // ...
}