9.4. The for Loop

The for loop executes a statement or a block of statements repeatedly until a specified expression evaluates to false. It takes the following form:

for ([initializers]; [expression]; [iterators]) statement

where

• initializers is a comma-separated list of expressions or assignment statements to initialize the loop counters.

• expression is an expression that can be implicitly converted to bool or a type that contains overloading of the true and false operators. The expression is used to test the loop-termination criteria.

• iterators are expression statements to increment or decrement the loop counters.

• statement is the embedded statement(s) to be executed.

The for statement executes the statement repeatedly as follows:

Because the test of expression takes place before the execution of the loop, a for statement executes zero or more times. All the expressions of the for statement are optional. Listing 9.5 shows the C# for loop in action.

Listing 9.5. C# for Loops

using System;

public class Test {
  public static void Main(string[] args) {
    //Simple for loop
    for (int i = 0; i < 10; ++i) {
      Console.WriteLine("single");
    }
    //For loop with two indices
    for (int i = 10, j = 1; (i > 0 || j < 12); --i, ++j) {
      Console.WriteLine("multiple");
    }
  }
}