|| Operator
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# || Operator (C# Reference)

Visual Studio 2008

Updated: October 2008

The conditional-OR operator (||) performs a logical-OR of its bool operands, but only evaluates its second operand if necessary.

## Remarks

The operation

```x || y
```

corresponds to the operation

```x | y
```

except that if x is true, y is not evaluated (because the result of the OR operation is true no matter what the value of y might be). This is known as "short-circuit" evaluation.

The conditional-OR operator cannot be overloaded, but overloads of the regular logical operators and operators true and false are, with certain restrictions, also considered overloads of the conditional logical operators.

## Example

In the following example, observe that the expression using || evaluates only the first operand.

```class ConditionalOr
{
static bool Method1()
{
Console.WriteLine("Method1 called");
return true;
}

static bool Method2()
{
Console.WriteLine("Method2 called");
return false;
}

static void Main()
{
Console.WriteLine("regular OR:");
Console.WriteLine("result is {0}", Method1() | Method2());
Console.WriteLine("short-circuit OR:");
Console.WriteLine("result is {0}", Method1() || Method2());
}
}
/*
Output:
regular OR:
Method1 called
Method2 called
result is True
short-circuit OR:
Method1 called
result is True
*/
```

## Change History

Date

History

Reason

October 2008

Corrected code example.

Customer feedback.

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