Csharp/CSharp Tutorial/Operator/Ternary Operator

Prevent a division by zero using the ? operator

<source lang="csharp">using System;

class Example {

 public static void Main() { 
   int result; 

   for(int i = -5; i < 6; i++) { 
     result = i != 0 ? 100 / i : 0; 
     if(i != 0)  
       Console.WriteLine("100 / " + i + " is " + result); 
   } 
 } 

}</source>

100 / -5 is -20
100 / -4 is -25
100 / -3 is -33
100 / -2 is -50
100 / -1 is -100
100 / 1 is 100
100 / 2 is 50
100 / 3 is 33
100 / 4 is 25
100 / 5 is 20

Simplest Data type cast operator

<source lang="csharp">using System; class MyDataType {

  public static explicit operator int(MyDataType li)   // Convert type
  {
     Console.WriteLine("explicit operator int");
     return 0;
  }
  public static explicit operator MyDataType(int x)    // Convert type
  {
     Console.WriteLine("public static explicit operator MyDataType");
     return new MyDataType();
  }

} class MainClass {

  static void Main()
  {
     MyDataType d = (MyDataType)5;
     int Five = (int)d;
     Console.WriteLine(Five);
  }

}</source>

public static explicit operator MyDataType
explicit operator int
0

The ? Operator

1. The ? operator is often used to replace certain types of if-then-else constructions.
2. The ? is called a ternary operator because it requires three operands.

It takes the general form

<source lang="csharp">Exp1 ? Exp2 : Exp3;</source>

1. where Exp1 is a bool expression, and Exp2 and Exp3 are expressions.
2. The type of Exp2 and Exp3 must be the same.

The value of a ? expression is determined like this:

1. Exp1 is evaluated.
2. If it is true, then Exp2 is evaluated and becomes the value of the entire ? expression.
3. If Exp1 is false, then Exp3 is evaluated, and its value becomes the value of the expression.

The ternary operator

<source lang="csharp">class MainClass {

 public static void Main()
 {
   int result;
   result = 10 > 1 ? 20 : 10;
   System.Console.WriteLine("result = " + result);
   result = 10 < 1 ? 20 : 10;
   System.Console.WriteLine("result = " + result);
 }

}</source>

result = 20
result = 10

Use ternary operator in Console.WriteLine function

<source lang="csharp">using System; class MainClass {

  static void Main()
  {
     int x = 10, y = 9;
     Console.WriteLine("x is{0} greater than y",
                           x > y          // Condition
                           ? ""           // Expression 1
                           : " not");     // Expression 2
     y = 11;
     Console.WriteLine("x is{0} greater than y",
                           x > y          // Condition
                           ? ""           // Expression 1
                           : " not");     // Expression 2
  }

}</source>

x is greater than y
x is not greater than y