C# 0 The Complete Reference

PART I

C h a p t e r   4 :  

O p e r a t o r s  

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PART IPART I

division. Thus, in the first test, 

d

 is 2 and the modulus operation is performed. The second 

test fails because 

d

 is set to zero, and the modulus operation is skipped, avoiding a divide-

by-zero error. Finally, the normal AND operator is tried. This causes both operands to be 

evaluated, which leads to a runtime error when the division-by-zero occurs.

Since the short-circuit operators are, in some cases, more efficient than their normal 

counterparts, you might be wondering why C# still offers the normal AND and OR 

operators. The answer is that in some cases you will want both operands of an AND or OR 

operation to be evaluated because of the side effects produced. Consider the following:

// Side effects can be important.

using System;

class SideEffects {

  static void Main() {

    int i;

    bool someCondition = false;

    i = 0;

    // Here, i is still incremented even though the if statement fails.

    if(someCondition & (++i < 100))

       Console.WriteLine("this won't be displayed");

    Console.WriteLine("if statement executed: " + i); // displays 1

    // In this case, i is not incremented because the short-circuit

    // operator skips the increment.

    if(someCondition && (++i < 100))

      Console.WriteLine("this won't be displayed");

    Console.WriteLine("if statement executed: " + i); // still 1 !!

  }

}

First, notice that the