Default Statement in C

Prerequisite – Control Statements in C
In C, the switch statement can have a default case, which is executed if none of the other cases match the value of the switch expression. The default case is optional, but it’s often used to provide a fallback option in case none of the other cases are appropriate.

Syntax:
The syntax for using the default case in a switch statement is as follows:

switch (expression) {
    case value1:
        // code to execute if expression == value1
        break;
    case value2:
        // code to execute if expression == value2
        break;
    // additional case statements...
    default:
        // code to execute if none of the other cases match
        break;
}

Examples:
Here’s examples that demonstrates the use of the default case in a switch statement:

Example-1:

#include <stdio.h>

int main() {
    int day = 8;

    switch (day) {
        case 1:
            printf("Monday\n");
            break;
        case 2:
            printf("Tuesday\n");
            break;
        case 3:
            printf("Wednesday\n");
            break;
        case 4:
            printf("Thursday\n");
            break;
        case 5:
            printf("Friday\n");
            break;
        case 6:
            printf("Saturday\n");
            break;
        case 7:
            printf("Sunday\n");
            break;
        default:
            printf("Invalid day\n");
            break;
    }

    return 0;
}

Output:

Invalid day

Example-2:

#include <stdio.h>

int main() {
    int age = 15;

    switch (age) {
        case 18:
            printf("You are eligible to vote!\n");
            break;
        case 21:
            printf("You are eligible to drink alcohol!\n");
            break;
        default:
            printf("You are not eligible for any special privileges.\n");
            break;
    }

    return 0;
}

In this example, the program uses a switch statement to check the value of the age variable. If age is equal to 18, the program prints a message saying that the person is eligible to vote. If age is equal to 21, the program prints a message saying that the person is eligible to drink alcohol. If age is any other value, the default statement is executed, and the program prints a message saying that the person is not eligible for any special privileges.

Output:

You are not eligible for any special privileges.

In this case, the value of age is 15, which doesn’t match any of the case statements. As a result, the default case is executed, and the program prints “You are not eligible for any special privileges.”

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