Switch Case in C

What is Switch Case in C ?

The switch case statement in C is a conditional statement that allows a program to perform different actions based on the value of an expression. It provides an efficient and readable way to handle multiple cases and avoid nested if-else statements, making the code more organized and easier to maintain.

The Syntax of Switch Case in C

The syntax of the switch case statement follows this structure:

switch(expression) {
    case constant1:
        // Code to execute when the expression is equal to constant1
    case constant2:
        // Code to execute when the expression is equal to constant2
    // Add more cases as needed
        // Code to execute when none of the cases match the expression

How Switch Case Works in C

When the switch case statement is encountered, the expression is evaluated once, and its value is compared with the values of each case. If there is a match, the corresponding block of code is executed until the break statement is reached. If no match is found, the code under the default label (if present) is executed.

Examples of Switch Case

In this section, we will walk through practical examples of switch case in C to deepen our understanding of its usage and flexibility.

Example 1: Calculating Days in a Month

#include <stdio.h>

int main() {
    int month, days;
    printf("Enter the month number (1-12): ");
    scanf("%d", &month);

    switch (month) {
        case 1: case 3: case 5: case 7: case 8: case 10: case 12:
            days = 31;
        case 4: case 6: case 9: case 11:
            days = 30;
        case 2:
            days = 28;
            printf("Invalid month number.");
            return 1;

    printf("Number of days in month %d: %d", month, days);
    return 0;

In this example, we use switch case to calculate the number of days in a given month. Depending on the month number provided by the user, the code executes the corresponding case to determine the number of days.

Example 2: Grade Classification

#include <stdio.h>

int main() {
    int score;
    printf("Enter your score (0-100): ");
    scanf("%d", &score);

    switch (score / 10) {
        case 10:
        case 9:
            printf("Grade: A");
        case 8:
            printf("Grade: B");
        case 7:
            printf("Grade: C");
        case 6:
            printf("Grade: D");
            printf("Grade: F");

    return 0;

In this example, the switch case statement is used to classify a student’s grade based on their score. The code divides the score by 10 and uses the resulting value to determine the grade.

Best Practices for Using Switch Case in C

To write clean, efficient, and bug-free code, it’s essential to follow best practices when using switch case in C. Here are some valuable tips to enhance your programming skills:

1. Always Include a Default Case

Including a default case in your switch statement ensures that if none of the cases match the expression, a fallback action is taken. This helps prevent unexpected behavior and provides a safety net for any unforeseen scenarios.

2. Limit the Number of Cases

While switch case can handle multiple cases, it’s best to keep the number of cases to a minimum. A long list of cases can make the code hard to read and maintain. If there are too many cases, consider using if-else statements instead.

3. Avoid Fall-Through

In C, switch cases “fall through” if there is no break statement. This means that if one case matches, the code execution continues to the next case without any further checks. Avoid fall-through unless it is intentional, as it can lead to unintended results.

4. Use Constants for Cases

Always use constants (literal values) for case labels rather than variables. Using variables can introduce potential bugs and make the code harder to understand.

5. Organize Cases Logically

Arrange your cases in a logical order to improve code readability. This will help you and other developers understand the flow of the switch statement more easily.

FAQs: Frequently Asked Questions About Switch Case in C

Here are some common questions that beginners often ask about switch case in C:

Q: Is the default case mandatory in a switch statement?

A: While the default case is not mandatory, it is considered a good practice to include it. The default case acts as a safety net, ensuring that if none of the cases match the expression, the code under the default label is executed.

Q: Can I use floating-point numbers in switch case?

A: No, switch case in C only works with integral data types, such as int and char. Floating-point numbers or other data types are not supported.

Q: Can I have multiple cases with the same code block?

A: Yes, you can group multiple cases together and have them share the same code block. This allows you to perform the same actions for different cases.

Q: What happens if I forget to include the break statement?

A: If you forget to include the break statement after a case, the code execution will “fall through” to the next case without any further checks. This may lead to unintended results and is generally avoided, except when intended.

Q: Can I use switch case for string comparison?

A: In standard C, switch case does not support string comparison directly. However, you can achieve string comparison by using a hash table or a series of if-else statements.

Q: Is switch case more efficient than if-else statements?

A: In general, switch case is more efficient than if-else statements when dealing with a larger number of cases. However, the difference in performance may vary based on the compiler and the complexity of the conditions.