Learning C# 3.0

The Conditional Operator

Although most operators are unary (they require one term, such as myValue++) or binary (they require two terms, such as a+b), there is one ternary operator, which requires three terms, named the conditional operator ( ? : ):

cond-expr ? expression1 :expression2

This operator evaluates a conditional expression (an expression that returns a value of type bool) and then invokes either expression1 if the value returned from the conditional expression is true, or expression2 if the value returned is false. The logic is: “if this is true, do the first; otherwise, do the second.” Example 4-5 illustrates this concept.

Example 4-5. The ternary operator is a simple kind of control flow statement; depending on the value of the expression, it can take one of two stated actions

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Example_4_5_ _ _ _Ternary_Operator
{
    class ValuesProgram
    {
        static void Main(  )
        {
            int valueOne = 10;
            int valueTwo = 20;

            int maxValue = valueOne > valueTwo ? valueOne : valueTwo;

            Console.WriteLine("ValueOne: {0}, valueTwo: {1}, maxValue: {2}",
              valueOne, valueTwo, maxValue);

        }
    }
}

The output looks like this:

ValueOne: 10, valueTwo: 20, maxValue: 20

In Example 4-5, the ternary operator is being used to test whether valueOne is greater than valueTwo. If so, the value of valueOne is assigned to the integer variable maxValue; otherwise, the value of valueTwo is assigned to maxValue.

As with the increment operator, ...