Using Range In Switch Case In C/C++

Using Range In Switch Case In C/C++

This extension allows you to specify a range of consecutive values in a single case label, which can be quite convenient for simplifying code when you need to perform the same actions for a range of values.

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':

Note:

You have to write ellipses (…)

Example:

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

// C program to illustrate
// using range in switch case
#include <stdio.h>
int main()
{
    int arr[] = { 1, 5, 15, 20 };
 
    for (int i = 0; i < 4; i++) {
        switch (arr[i]) {
            // range 1 to 6
        case 1 ... 6:
            printf("%d in range 1 to 6\n", arr[i]);
            break;
            // range 19 to 20
        case 19 ... 20:
            printf("%d in range 19 to 20\n", arr[i]);
            break;
        default:
            printf("%d not in range\n", arr[i]);
            break;
        }
    }
    return 0;
}

Output

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

Complexity Analysis

1. Time Complexity: O(n)
   • Time complexity is a measure of how the execution time of an algorithm or program scales with the input size.
   • In this case, the algorithm or code snippet has a time complexity of O(n), where ‘n’ represents the size of the array ‘arr.’
   • This means that as the size of the input array ‘arr’ increases, the time it takes for the algorithm or code to run will also increase linearly.
2. Auxiliary Space Complexity: O(1)
   • Auxiliary space complexity refers to the amount of additional memory space used by the algorithm or code, excluding the input data.
   • Auxiliary space complexity of O(1) indicates that the algorithm or code uses a constant amount of extra memory space regardless of the input size.
   • In other words, the amount of additional memory used does not depend on the size of the input array ‘arr.’

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.

FAQ- Using Range In Switch Case In C/C++