Control Structures: Switch

Another type of conditional statement is the switch statement. This is a variation of if/else statements, which is visually more compact and also allows for faster compilation.

Switch Statements

General Structure

    switch (expression)

    {

        case first-constant:

            code

            break

        case second-constant:

            code

            break

        default:

            code

            break

    }

Python

Python does not formally support switch statements. There are ways to emulate them, but I'll leave that for another discussion.

C++

    switch (month)

    {

        case 1:

            cout << "The month is January." << endl;

            break;

        case 2:

            cout << "The month is February." << endl;

            break;

        case 3:

            cout << "The month is March." << endl;

            break;

        case 4:

            cout << "The month is April." << endl;

            break;

        case 5:

            cout << "The month is May." << endl;

            break;

        case 6:

            cout << "The month is June." << endl;

            break;

        case 7:

            cout << "The month is July." << endl;

            break;

        case 8:

            cout << "The month is August." << endl;

            break;

        case 9:

            cout << "The month is September." << endl;

            break;

        case 10:

            cout << "The month is October." << endl;

            break;

        case 11:

            cout << "The month is November." << endl;

            break;

        case 12:

            cout << "The month is December." << endl;

            break;

        default:

            cout << "Invalid month." << endl;

    }

Java

    switch (month) {

        case 1:

            System.out.println("The month is January.");

            break;

        case 2:

            System.out.println("The month is February.");

            break;

        case 3:

            System.out.println("The month is March.");

            break;

        case 4:

            System.out.println("The month is April.");

            break;

        case 5:

            System.out.println("The month is May.");

            break;

        case 6:

            System.out.println("The month is June.");

            break;

        case 7:

            System.out.println("The month is July.");

            break;

        case 8:

            System.out.println("The month is August.");

            break;

        case 9:

            System.out.println("The month is September.");

            break;

        case 10:

            System.out.println("The month is October.");

            break;

        case 11:

            System.out.println("The month is November.");

            break;

        case 12:

            System.out.println("The month is December.");

            break;

        default:

            System.out.println("Invalid month");

            break;

    }

• Once again, C++ and Java's syntax are remarkably similar. In fact, they are identical other than their print statements. Some things to note:
• The cases are equivalent to if or else if, the default is equivalent to else.
• The case expression supports more than just integers (it also supports integer variations and characters), but whatever is used must be a constant.
• There is NO punctuation after the expression.
• There is a colon after each case.
• You also don't need to include the "break" statement under the "default" case since it's the end of the loop.
• None of the whitespace is necessary. You could just as easily write each case like:
  case 1:    System.out.println("The month is January.");    break;
• However, I chose to write the examples this way for readability.