Using Range in switch Case in C

You all are familiar with switch case in C, but did you know you can use a range of numbers instead of a single number or character in the case statement? Range in switch case can be useful when we want to run the same set of statements for a range of numbers so that we do not have to write cases separately for each value.

• That is the case range extension of the GNU C compiler and not standard C.
• You can specify a range of consecutive values in a single case label.

Syntax

The syntax for using range case is:

case low ... high:

It can be used for a range of ASCII character codes like this:

case 'A' ... 'Z':

You need to Write spaces around the ellipses ( ... ). For example, write this:

// Correct - case 1 ... 5: 
// Wrong - case 1...5: 

The below program illustrates the use of range in switch case.

1 in range 1 to 6
5 in range 1 to 6
15 not in range
20 in range 19 to 20

Complexity Analysis

• Time Complexity: O(n), where n is the size of array arr.
• Auxiliary Space: O(1)

Error conditions

1. low > high: The compiler gives an error message.
2. Overlapping case values: If the value of a case label is within a case range that has already been used in the switch statement, the compiler gives an error message.

Exercise

• You can try the above program for a char array by modifying the char array and case statement.