Switch

From Game Editor

A switch statement is a special instance of an if else if else ... statement.

A switch statement takes the following form:

switch ( expression ) {
  case constant_1 : 
    statements;
  case constant_2 : 
    statements;
  ...
  default : 
    statements;
}

Example:

 char keydown = getKey();
 switch ( keydown ) {
   case 'w':
     y -= 5;
     break;
   case 'a':
     x -= 5;
     break;
   case 's':
     y += 5;
     break;
   case 'd':
     x += 5;
     break;
   default:
     PlaySound("annoying-beep.wav", 1, 1);
 }

The default condition is optional.

The break statement in each case condition is optional, but recommended. If you do not include a break for each case, each subsequent case would also be executed.

Bad example:

 char keydown = getKey();
 switch ( keydown ) {
   case 'w':
     y -= 5;
   case 'a':
     x -= 5;
   case 's':
     y += 5;
   case 'd':
     x += 5;
   default:
     PlaySound("annoying-beep.wav", 1, 1);
 }

In the bad example, if keydown has the value 'w', then y will decremented by 5, x will be decremented by 5, y will incremented by 5, x will be incremented by 5 and the annoying sound will be played.

A switch statement may be easier to read than nested if statements. The "wasd" movement example might be written like this with if statements:

if ( keydown == 'w' ) {
  y -= 5;
} else if ( keydown == 'a' ) {
  x -= 5;
} else if ( keydown == 's' ) {
  y += 5;
} else if ( keydown == 'd' ) {
  x += 5;
} else {
  PlaySound("annoying-beep.wav", 1, 1);
}

Even though this code is still clear for this simple example, the switch statement is much less to type.