What do {} do in C#

Question

This is a really simple question but one I would like to know before moving forward so I understand the process.

In the tutorial I am following I was using an if statement. If you do the code below you don't need to use {}

if (userValue == "1")
    message = "You won a new car!"; 

But if you use more than one line of code you do need {}.

if (userValue == "1")
{
    WriteLine ("You won a new car!");
    ReadLine ();
}

Can someone explain to me in very simple terms why this is the case? I just need a rule of thumb so I can understand why. Nothing overly complicated I'm just a beginner. I understand that they identify a block of code but am not sure why this makes a difference between one or two lines?

Answer 1

The {} indicates a block of code. If you have more than one statement that you want to be performed if the if is true, then you need to use these.

Example: Without the {} this block:

if (userValue == "1")
   WriteLine ("You won a new car!");
   ReadLine ();

Would perform the ReadLine() command whether or not the userValue is equal to 1.

Contrast that with the one with curly braces:

if (userValue == "1")
{
    WriteLine ("You won a new car!");
    ReadLine ();
}

Now in case the userValue is not equal to 1, both command inside the curly braces are skipped and the execution continues with the next statement after the } sign.