C program to print number of days in a month using switch case

Example
Input

Input month number: 3

Output

Total number of days = 31

Logic to print number of days in month using switch...case

Total days in a month is given by below table.

Month	Total days
January, March, May, July, August, October, December	31 days
February	28/29 days
April, June, September, November	30 days

Step by step descriptive logic to print number of days in a month using switch...case.

1. Input month number from user. Store it in some variable say month.
2. Switch the value of month i.e. switch(month) and match with cases.
3. There can be 12 possible values (choices) of month i.e. from 1 to 12. Hence, write 12 cases inside switch and one default case as else block.
4. Print 31 for case 1, 3, 5, 7, 8, 10, 12.
5. Print 30 for case 4, 6, 9, 11.
6. Print 28/29 for case 2.
7. Print invalid input for default case.

/**
 * C program to print number of days in a month using switch case 
 */

#include <stdio.h>

int main()
{
    int month;

    /* Input month number from user */
    printf("Enter month number(1-12): ");
    scanf("%d", &month);

    switch(month)
    {
        case 1: 
            printf("31 days");
            break;
        case 2: 
            printf("28/29 days");
            break;
        case 3: 
            printf("31 days");
            break;
        case 4: 
            printf("30 days");
            break;
        case 5: 
            printf("31 days");
            break;
        case 6: 
            printf("30 days");
            break;
        case 7: 
            printf("31 days");
            break;
        case 8: 
            printf("31 days");
            break;
        case 9: 
            printf("30 days");
            break;
        case 10: 
            printf("31 days");
            break;
        case 11: 
            printf("30 days");
            break;
        case 12: 
            printf("31 days");
            break;
        default: 
            printf("Invalid input! Please enter month number between 1-12");

    }

    return 0;
}

/*
Output :

Enter month number(1-12): 3
31 days
*/

best approach

/**
 * C program to print number of days in a month using switch case
 */

#include <stdio.h>

int main()
{
    int month;

    /* Input month number from user */
    printf("Enter month number(1-12): ");
    scanf("%d", &month);

    switch(month)
    {
        /* Group all 31 days cases together */
        case 1:
        case 3:
        case 5:
        case 7:
        case 8:
        case 10:
        case 12: 
            printf("31 days");
            break;

        /* Group all 30 days cases together */
        case 4:
        case 6:
        case 9:
        case 11: 
            printf("30 days");
            break;

        /* Remaining case */
        case 2: 
            printf("28/29 days");
            break;

        default: 
            printf("Invalid input! Please enter month number between 1-12");
    }

    return 0;
}

/*
Output :

Enter month number(1-12): 3
31 days
*/