C# Logical Operators

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C# Logical Operators are used in logical expressions and the returned value is definitely bool type value. To demonstrate the examples clearly, we'll assume two bool variables are defined as A=true and B=false.

Operator	Name	Usage	Description	Examples
!	logical negation operator	!A	Not A. It returns true if A is false and returns false if A is true.	bool C = !A; //C is false because A is true.
&	Logical AND	A & B	A and B. It returns true only if both A and B are true otherwise false	bool C = A & B; //C is false because B is false.
\|	Logical OR	A \| B	A or B. It returns false only if both A and B are false otherwise true	bool C = A \| B; //C is true because A is true.
^	Logical XOR	A ^ B	A XOR B. It returns true if only one of A or B is true otherwise false	bool C = A ^ B; //C is true because only A is true.
&&	Conditional AND	A && B	Same as Logical AND but only evaluate B if A is true	bool C = A && B; //C is false because B is false.
\|\|	Conditional OR	A \|\| B	Same as Logical OR but only evaluate B if A is false	bool C = A \|\| B; //C is true because A is true.

Example 01-10-01

Select

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									20
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									using System;

namespace TestLogicalOperators
{
    class Program
    {
        static void Main(string[] args)
        {
            bool x, y;
            x = false;
            y = true;
            Console.WriteLine("x={0}, y={1}", x, y);
            Console.WriteLine("!x={0}, !y={1}", !x, !y);
            Console.WriteLine("x&y={0}", x&y);
            Console.WriteLine("x|y={0}", x|y);
            Console.WriteLine("x^y={0}", x^y);
            Console.WriteLine("x&&y={0}", x && y);
            Console.WriteLine("x||y={0}", x ||    y);
            Console.Read();
        }
    }
}

								

Output

									x=False, y=True
!x=True, !y=False
x&y=False
x|y=True
x^y=True
x&&y=False
x||y=True
								

Line 9-11: Declare 2 bool variables x, y and its initial values.
Line 12: Output x, y.
Line 13: Output !x and !y. ! operator reverses its right operand
Line 14: Output the result of x&y and it is false.
Line 15: Output the result of x|y and it is true.
Line 16: Output the result of x^y and it is true because x and y have the different value.
Line 17: Output the result of x && y and it is false. x && y is the same as x&&y.
Line 18: Output the result of x || y and it is true. x || y is the same as x||y.

Note
The spaces between an operator and its operand will be neglected when it is compiled. But the spaces make the code more readable.

The following is the full value table for two oprands A and B.

A	B	!A	!B	A&B	A\|B	A^B	A&&B	A\|\|B
true	true	false	false	true	true	false	true	true
true	false	false	true	false	true	true	false	true
false	true	true	false	false	true	true	false	true
false	false	true	true	false	false	false	false	false

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