C Switch

Switch Statement

Instead of writing many if..else statements, you can use the switch statement.

The switch statement selects one of many code blocks to be executed:

This is how it works:

• The switch expression is evaluated once
• The value of the expression is compared with the values of each case
• If there is a match, the associated block of code is executed
• The break statement breaks out of the switch block and stops the execution
• The default statement is optional, and specifies some code to run if there is no case match

The example below uses the weekday number to calculate the weekday name:

The break Keyword

When C reaches a break keyword, it breaks out of the switch block.

This will stop the execution of more code and case testing inside the block.

When a match is found, and the job is done, it's time for a break. There is no need for more testing.

The default Keyword

The default keyword specifies some code to run if there is no case match:

int day = 2;
switch () {
 1:
    printf("Monday");
    ;
 2:
    printf("Sunday");
    ;
}