Switch Case

A switch statement allows a variable to be tested for equality against a list of values. Each value is called a case, and the variable being switched on is checked for each switch case.

Syntax:

switch(expression) {

    case constant-expression  :
        statement(s);
        break; /* optional */

    case constant-expression  :
        statement(s);
        break; /* optional */

    /* you can have any number of case statements */
    default : /* Optional */
        statement(s);
}

When the variable being switched on is equal to a case, the statements following that case will execute until a break statement is reached.

The break statement interrupts the flow inside switch block and the execution continues outside the block.

When a break statement is reached, the switch terminates, and the flow of control jumps to the next line following the case.

Not every case needs to contain a break. If no break appears, the flow of control will fall through to subsequent cases until a break is reached.

We’ll discuss about break statement in loops

A switch statement can have an optional default case, which must appear at the end of the switch. The default case can be used for performing a task when none of the cases is true. No break is needed in the default case.

Eg:

#include <stdio.h>

int main() {
    char ch;

    printf("Enter a color code (r/g/b/y)\n");
    scanf("%c", &ch);

    switch (ch) {
    case 'r':
        printf("red color");
        break;
    case 'b':
        printf("Blue color");
        break;
    case 'g':
        printf("Green color");
        break;
    case 'y':
        printf("Yellow color");
        break;
    default:
        printf("undefined color");
    }
    return 0;
}

Output

Enter a color code (r/g/b/y)
g
Green color