Switch statement

Switch statements function somewhat similarly to the if statement we used before, as it allows us to execute one code block among many alternatives. In some cases, using a switch statement has the advantage of being much easier to read and write compared to a long if-else ladder.

The switch statement is based on a variable that is tested for equality against a list of values, each one called a "case" of that variable.

Syntax

It's more complicated to explain than to see, so here's the generic syntax:

switch (variable) {
    case value1:
        // code block
        break;
    case value2:
        // code block
        break;
    case value3:
        // code block
        break;
    // more cases...

    // optional
    default:
        // code block
}

The value of variable is compared with every possible value of each case and there's a match the associated block of code is executed. break is used to interrupt the execution and if no match is found break is never executed, therefore the default case (optional) will compile instead. In the default case break isn't needed.

A practical example:

switch-case-week.cpp

#include <iostream>
using namespace std;

int main() {
    int day;

    cout << "Insert a day of the week (from 1 to 7):" << endl;
    cin >> day;

    // switch statement
    switch (day) {
        case 1:
            cout << "Monday" << endl;
            break;
        case 2:
            cout << "Tuesday" << endl;
            break;
        case 3:
            cout << "Wednesday" << endl;
            break;
        case 4:
            cout << "Thursday" << endl;
            break;
        case 5:
            cout << "Friday" << endl;
            break;
        case 6:
            cout << "Saturday" << endl;
            break;
        case 7:
            cout << "Sunday" << endl;
            break;

        default:
            cout << "Input not valid" << endl;
    }

    return 0;
}