switch, case, default

This is an alternate, simpler form of conditional. It is used to check a variable against a a set of fixed values. A switch statement does what we call “falling-through”. If not broken out of with break, it will execute every statement from the first true one downwards. Switch statements can also ahve a default clause, which will only happen if no other conditions are true, or if it is fallen through to.

Usage:

int x = 4;
int y = 3;
int z = 8;

switch (x){

	case 0: { 
		//do something if x is 0
		y = 2*z;
		break; //but jump out of the switch, we don't want to go to "case 1."
	} case 1:{
		y = x + 2;
		//do something if x is 1 OR 2, since we have no break statement to keep it from continuing on into case 2.
		//this is *not* recommended.
	} case 2:{
		z = x * y;
		break;
	} default:{
		z = 25;
		break;
	}
}

In this sample program, if x is zero, we just set y equal to double the value of z. If the value of x is 1, then we set y equal to x + 2, which is going to be 3, naturally, and then we continue on to set z equal to x * y. If the value of x is 2, then we just set z to x * y, we don’t mess with the value of y, and if the value of x is anything else, we set z equal to 25.