What is the OR operator in an IF statement

Question

In C#, how do I specify OR:

if(this OR that) {do the other thing}

I couldn\'t find it in the help.

Update:

Answer 1

The conditional or operator is ||:

if (expr1 || expr2) {do stuff}

if (title == "User greeting" || title == "User name") {do stuff}

The conditional (the OR) and it's parts are boolean expressions.

MSDN lists the C# operators in precedence order here http://msdn.microsoft.com/en-us/library/6a71f45d.aspx . And the MSDN page for boolean expressions is http://msdn.microsoft.com/en-us/library/dya2szfk.aspx .

If you are just starting to learn programming, you should read up on Conditional Statements from an introductory text or tutorial. This one seems to cover most of the basics: http://www.functionx.com/csharp/Lesson10.htm .

Answer 2

The OR operator is a double pipe:

||

So it looks like:

if (this || that) 
{
  //do the other thing
}

EDIT: The reason that your updated attempt isn't working is because the logical operators must separate valid C# expressions. Expressions have operands and operators and operators have an order of precedence.

In your case, the == operator is evaluated first. This means your expression is being evaluated as (title == "User greeting") || "User name". The || gets evaluated next. Since || requires each operand to be a boolean expression, it fails, because your operands are strings.

Using two separate boolean expressions will ensure that your || operator will work properly.

title == "User greeting" || title == "User name"

Answer 3

Or is ||

And is &&

Update for changed question:

You need to specify what you are comparing against in each logical section of the if statement.

if (title == "User greeting" || title == "User name") 
{
    // do stuff
}

Answer 4

In the format for if

if (this OR that) 

this and that are expression not values. title == "aaaaa" is a valid expression. Also OR is not a valid construct in C#, you have to use ||.

Answer 5

Just for completeness, the || and && are the conditional version of the | and & operators.

A reference to the ECMA C# Language specification is here.

From the specification:

3 The operation x || y corresponds to the operation x | y, except that y is evaluated only if x is false.

In the | version both sides are evaluated.

The conditional version short circuits evaluation and so allows for code like:

if (x == null || x.Value == 5)
    // Do something 

Or (no pun intended) using your example:

if (title == "User greeting" || title == "User name") 
    // {do stuff} 

Answer 6

you need

if (title == "User greeting" || title == "User name") {do stuff};