C# 0 The Complete Reference

==

 and 

!=

.

However, the comparison operators, 

<

,

>

,

<=

, or 

>=

, can be applied only to those types 

that support an ordering relationship. Therefore, all of the relational operators can be 

applied to all numeric types. However, values of type 

bool

 can only be compared for 

equality or inequality since the 

true

 and 

false

 values are not ordered. For example, 

true > false

 has no meaning in C#.

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P a r t   I :  

T h e   C #   L a n g u a g e

For the logical operators, the operands must be of type 

bool

, and the result of a logical 

operation is of type 

bool

. The logical operators, 

&

,

|

,

^

, and 

!

, support the basic logical 

operations AND, OR, XOR, and NOT, according to the following truth table:

p

q

p & q

p | q

p ^ q

!p

False

False

False

False

False

True

True

False

False

True

True

False

False

True

False

True

True

True

True

True

True

True

False

False

As the table shows, the outcome of an exclusive OR operation is true when one and only 

one operand is true.

Here is a program that demonstrates several of the relational and logical operators:

// Demonstrate the relational and logical operators.

using System;

class RelLogOps {

  static void Main() {

    int i, j;

    bool b1, b2;

    i = 10;

    j = 11;

    if(i < j) Console.WriteLine("i < j");

    if(i <= j) Console.WriteLine("i <= j");

    if(i != j) Console.WriteLine("i != j");

    if(i == j) Console.WriteLine("this won't execute");

    if(i >= j) Console.WriteLine("this won't execute");

    if(i > j) Console.WriteLine("this won't execute");

    b1 = true;

    b2 = false;

    if(b1 & b2) Console.WriteLine("this won't execute");

    if(!(b1 & b2)) Console.WriteLine("!(b1 & b2) is true");

    if(b1 | b2) Console.WriteLine("b1 | b2 is true");

    if(b1 ^ b2) Console.WriteLine("b1 ^ b2 is true");

  }

}

The output from the program is shown here:

i < j

i <= j

i != j

!(b1 & b2) is true

b1 | b2 is true

b1 ^ b2 is true

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