C++ switch

The switch statement in C++ is a control flow statement that allows a program to evaluate the value of an expression and execute a block of code based on that value. It’s often used as an alternative to long chains of if-else statements.

The basic syntax of a switch statement is as follows:

switch (expression) {
    case constant1:
        // code to execute if expression equals constant1
        break; // optional; exits the switch block
    case constant2:
        // code to execute if expression equals constant2
        break;
    // ...
    default:
        // code to execute if expression doesn't match any case
        break;
}

Here’s an example of a switch statement:

#include <iostream>

int main() {
    int choice;
    std::cout << "Enter a number (1-3): ";
    std::cin >> choice;

    switch (choice) {
        case 1:
            std::cout << "You chose option 1." << std::endl;
            break;
        case 2:
            std::cout << "You chose option 2." << std::endl;
            break;
        case 3:
            std::cout << "You chose option 3." << std::endl;
            break;
        default:
            std::cout << "Invalid choice." << std::endl;
            break;
    }

    return 0;
}

In this example:

• The user is prompted to enter a number.
• The program then uses a switch statement to evaluate the value of choice.
• If choice matches a case constant, the corresponding code block is executed. In this case, it prints a message.
• If choice doesn’t match any of the case constants, the default case is executed.

Remember to include break statements after each case to prevent “fall-through” behavior. Without break, the code will continue to execute the statements of subsequent cases.

The default case is optional. It provides a fallback in case none of the case constants match the expression.

Note that the expression inside the switch statement must be of an integral type (like int, char, enum, etc.). It cannot be a floating-point type or a string.

The switch statement is a useful tool for efficiently handling multiple possible values of a variable. However, it’s important to use it judiciously and consider using other control structures or data structures when they may be more appropriate.