Selection

From TRCCompSci - AQA Computer Science
Revision as of 19:49, 16 December 2016 by QuantumFluctuator (talk | contribs)
Jump to: navigation, search

Selection uses if statements and switch statements.

  • if statements work by performing an action only if a condition is reached.
1 if (a > b)
2   {
3     Console.WriteLine("A is greater than B");
4   }

This can also be paired with else, which will perform an action if the "if" condition is not met.

  • switch is basically a combined if and if else statement, and is used for a lot of different options.
1 switch(x)
2   { 
3     case 1:
4       x++;
5       break;
6     case 2:
7       x--;
8       break;
9   }

Default is an optional part of the switch method, which is used in case none of the other conditions are met.

 1 switch(x)
 2   { 
 3     case 1:
 4       x++;
 5       break;
 6     case 2:
 7       x--;
 8       break;
 9     default:
10       x*= x;
11       break;
12   }

Nesting

Both if and switch statements can be nested, meaning that one statement can be contained within another. <syntaxhighlight lang="csharp" line>if (a > b)

 {
   if (b > 50)
     {
       Console.WriteLine("b is a very large number!");
     }
 }