C++ Switch Case Control Structure

Introduction

In this tutorial, we will learn about the switch case control structure in C++.

A switch statement allows a variable to be tested against multiple constant values. Each value is called a case, and the variable being checked is compared to each case until a match is found.

Switch case is often used as a cleaner alternative to writing multiple if-else-if statements when checking a variable against many possible values.

Key Points about Switch Case in C++

• The expression inside switch() must be of integral type (e.g., int, char, enum).
• Floating-point values are not allowed.
• Each case must have a constant value (variable values are not allowed).
• break is used to exit the switch block after a case executes. Without break, execution will fall through to the next case.
• The default case is optional but useful when no case matches.

Syntax of Switch Case in C++

switch(expression) {
    case constant1:
        // statements
        break;  // optional

    case constant2:
        // statements
        break;  // optional

    // you can have multiple cases

    default:
        // statements (optional)
}

switch(expression) {
    case constant1:
        // statements
        break;  // optional

    case constant2:
        // statements
        break;  // optional

    // you can have multiple cases

    default:
        // statements (optional)
}

Flowchart of Switch Case Statement

Example Program: Print Day of the Week

#include <iostream>
using namespace std;

int main() {
    int num;
    cout << "Enter a number between 1 and 7: ";
    cin >> num;

    switch(num) {
        case 1:
            cout << "Monday";
            break;
        case 2:
            cout << "Tuesday";
            break;
        case 3:
            cout << "Wednesday";
            break;
        case 4:
            cout << "Thursday";
            break;
        case 5:
            cout << "Friday";
            break;
        case 6:
            cout << "Saturday";
            break;
        case 7:
            cout << "Sunday";
            break;
        default:
            cout << "Invalid Input";
    }

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    int num;
    cout << "Enter a number between 1 and 7: ";
    cin >> num;

    switch(num) {
        case 1:
            cout << "Monday";
            break;
        case 2:
            cout << "Tuesday";
            break;
        case 3:
            cout << "Wednesday";
            break;
        case 4:
            cout << "Thursday";
            break;
        case 5:
            cout << "Friday";
            break;
        case 6:
            cout << "Saturday";
            break;
        case 7:
            cout << "Sunday";
            break;
        default:
            cout << "Invalid Input";
    }

    return 0;
}

Output

Enter a number between 1 and 7: 3
Wednesday

Enter a number between 1 and 7: 3
Wednesday

Explanation of the Example

1. The user enters a number (1–7).
2. The switch(num) checks the entered number against each case.
3. If num == 3, the output is "Wednesday".
4. The break statement ensures the program exits the switch once a match is found.
5. If no case matches, the default case runs.

Advantages of Switch Case over If-Else

✅ Cleaner and more readable when checking multiple values.
✅ Better performance in some cases since the compiler optimizes switch statements.
✅ Avoids writing long chains of if-else-if conditions.

Final Notes

• Use switch-case when dealing with fixed, known values.
• Use if-else when working with ranges or complex conditions (>, <, ==, etc.).