Switch Statements in

About Switch Statements

Like other languages, C++ also provides a switch statement. Switch statements are a shorter way to write long if ... else if statements. To make a switch, we start by using the keyword switch followed by an integer. We then declare each one of the conditions with the case keyword. We can also declare a default case, that will run when none of the previous case conditions match. Each case should end with a break (or a return) statement.

int price{0};
int adults{3};
int kids{2};

switch (int group_size{adults + kids}) {
    case 1:
        price = 50;
        break;
    case 2:
        price = 70;
        break;
    default:
        price = group_size * 30;
}

Fall-through

One important thing about the switch construct is that the code will continue to execute until it is stopped by a break (or a return) statement. This can lead to unexpected behavior.

int adults{1};
int kids{0};
switch (int group_size{adults + kids}) {
    case 1:
        price = 50;
    case 2:
        price = 70;
    default:
        price = group_size * 30;
}
// price will be 30!

The main use case for this continued execution feature is a statement that has several labels. Multiple switch results can map to the same piece of code to be executed. This way - in a booking app, for example - the called function for group sizes 2 and 3 can be the same:

switch (group_size) {
case 1:
    book_room();
    break;
case 2:
case 3:
    book_apartment(group_size);
    break;
default:
    book_house(group_size);
}
// book_apartment happens wheng roup_size is 2 or 3