How do you accept multiple values for a switch case?

Question

How does one accept more than one value for a single case in C++? I know you can make a range of values for one case (e.g. case 1..2) in some other languages, but it doesn't seem to be working in C++ on Xcode.

int main() {
    int input;
    cin >> input;
    switch (input) {
        case 1:
            cout << "option 1 \n";
            break;
        case 2..3: //This is where the error occurs
            cout << "option 2 and 3 \n";
            break;
        
        default:
            break;
    }
    return 0;
}

The program shows an error saying "Invalid suffix '.3' on floating constant" where the range is.

Advice -- do not use another computer language as a guide in writing C++ code. If you go down that road of trying to make C++ look like your other favorite computer language, you will wind up with buggy code, inefficient programs, or code that looks plain weird to a C++ programmer. — PaulMcKenzie, Aug 04 '20 at 15:23
To be honest, any decent book, tutorial or class should have taught you how to do this. — Some programmer dude, Aug 04 '20 at 15:24
I have found that there is a lot of syntax in other languages that doesn't work in C++. — Eljay, Aug 04 '20 at 15:25

score 6 · Accepted Answer · answered Aug 04 '20 at 15:23

6

You can "fall through" by having sequential case statements without a break between them.

switch (input) {
    case 1:
        cout << "option 1 \n";
        break;
    case 2:
    case 3:
        cout << "option 2 and 3 \n";
        break;
    
    default:
        break;
}

Note that some compilers support range syntax like case 50 ... 100 but this is non-standard C++ and will likely not work on other compilers.

answered Aug 04 '20 at 15:23

Cory Kramer

114,268
16
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1

Worth noting also that large ranges are better checked in an if/else block. – sweenish Aug 04 '20 at 15:34

score 5 · Answer 2 · answered Aug 04 '20 at 15:23

You could simply do:

switch (input) {
        case 1:
            cout << "option 1 \n";
            break;
        case 2: [[fallthrough]]
        case 3:
            cout << "option 2 and 3 \n";
            break;
        default:
            break;
    }

Note that case 2 ... 3 is called case ranges, and is a non-standard gcc extension that you could use.

score 2 · Answer 3 · answered Aug 04 '20 at 15:22

You can't do a range of values, but you can do multiple values:

switch (input) {
    case 1:
        cout << "option 1 \n";
        break;
    case 2: case 3: case 4:
        cout << "option 2 or 3 or 4\n";
        break;
    
    default:
        break;
}

score 0 · Answer 4 · answered Aug 04 '20 at 15:24

0

You need to use spaces between them with three(...)

int main() {
    int input;
    cin >> input;
    switch (input) {
        case 1:
            cout << "option 1 \n";
            break;
        case 2 ... 3: //This is where the error occurs
            cout << "option 2 and 3 \n";
            break;
        
        default:
            break;
    }
    return 0;
}

answered Aug 04 '20 at 15:24

Aayush Mall

963
8
20

2

This is true, but it's not standard c++, it's a gcc extension. – cigien Aug 04 '20 at 15:27

How do you accept multiple values for a switch case?

4 Answers4