C Switch Statement

C switch statement

Created By: chatGPT

The switch statement in C is used for multi-way branch selection. It evaluates an expression and executes the corresponding case block that matches the expression's value. It can be much clearer than using multiple if-else statements, especially when checking the same variable against different values.

switch (expression) {
    case constant1:
        // Code block for constant1
        break;
    case constant2:
        // Code block for constant2
        break;
    default:
        // Code block if no case matches
}

Here's a simple example of a switch statement that evaluates the day of the week. Based on the value provided, it outputs the corresponding name of the day.

int day = 3;

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");
}

In this example, if the value of day is 3, the output will be Wednesday. Notice the use of break, which is crucial. If we omit the break statement, execution will continue into the subsequent case until a break is encountered or the switch finishes. This behavior is called fall-through.

int day = 2;

switch (day) {
    case 1:
        printf("Day 1\n");
    case 2:
        printf("Day 2\n");
    case 3:
        printf("Day 3\n");
}
// Output: 
// Day 2
// Day 3

You can also use arithmetic or string comparisons in switch cases. However, each case must be a unique constant. Strings cannot be directly used in switch statements in C, but they can be compared using if-else or by using a separate enumeration or integer representation.

#include <stdio.h>

int main() {
    char grade = 'B';
    switch (grade) {
        case 'A':
            printf("Excellent!\n");
            break;
        case 'B':
            printf("Well done!\n");
            break;
        case 'C':
            printf("Good job!\n");
            break;
        default:
            printf("Grade not recognized\n");
    }
    return 0;
}