Switch Statement 🎚️

Sometimes when using if statements, you may end up doing something like this:

int target_value = 0;

if (target_value == 1) {
    printf("1");
} else if (target_value == 2) {
    printf("2");
} else if (target_value == 3 || target_value == 4) {
    printf("3 or 4");
} else if (target_value == 5) {
    printf("5");
} else {
    printf("Didn't match anything!");
}

However you can achieve the same thing using a switch statement.

int target_value = 0;

switch(target_value) {
    case 1:
        printf("1");
        break;
    case 2:
        printf("2");
        break;
    case 3:
    case 4:
        printf("3 or 4");
        break:
    case 5:
        printf("5");
        break;
    default:
        printf("Didn't match anything!");
}

Lets take a look at a general switch statement to understand how to write one:

switch(target_value) {
    case value_1:
        // Some code
        break;
    case value_2:
        // Some code
        break;
    ...
    default:
        // Some code
}

target_value

is the value we want to check.

case value_1:

is a case. Cases in a switch statement are the different values that we check is equal to the target_value.

Tip

Don’t forget the colon after the value for the case!

break

is a statement that, when used inside a case, will exit the switch. Break statements are actually optional and if omitted, your program will execute the next case’s code if it exists. This behaviour is known as fall-through.

Ex.

The code below will print “34”.

switch(3) {
    case 3:
        printf("3");
    case 4:
        printf("4");
}

default

is a special type of case that the program runs if target_value could not be matched. Think of this as an else statement for switches.

---

Tasks 🎯

Make a program, using a switch statement, that converts a number from 1-7 to a day of the week.

For example, 1 would be converted into “Sunday”, 2 would be converted into “Monday”, and so forth. If you get a number that’s not 1-7, then print “Number must be 1-7!”.

#include <stdio.h>

int main() {
    int day_of_week = 0;

    printf("Please enter a number from 1-7 to convert to a day of the week:\n");
    scanf("%d", &day_of_week);

    switch(day_of_week) {
        case 1:
            printf("Sunday");
            break;
        case 2:
            printf("Monday");
            break;
        case 3:
            printf("Tuesday");
            break;
        case 4:
            printf("Wednesday");
            break;
        case 5:
            printf("Thursday");
            break;
        case 6:
            printf("Friday");
            break;
        case 7:
            printf("Saturday");
            break;
        default:
            printf("Number must be 1-7!");
    }

    return 0;
}

Solution ✅

#include <stdio.h>

int main() {
    int condition = 1; // Setting this to any non-zero value would mean true.

    if (condition) {
        printf("True");
    }

    if (!condition) {
        printf("False");
    }

    return 0;
}