Question

Complete the following program in C; Have the user input the current month and return the previous month.

E.g. input -> 3, returns 2
input -> 1, returns 12

#include <stdio.h>
#include <stdlib.h>

/* Write a function called previous_month that returns the previous month.
start with the following code */

enum month {jan = 1, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec};
typedef enum month month;

int main() {

            return0;

}

Answer 1

#include <stdio.h>
#include <stdlib.h>

/* Write a function called previous_month that returns the previous month.
start with the following code */


enum month {
    jan = 1, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec
};
typedef enum month month;

enum month previous_month(enum month m) {
    if (m == jan)
        return dec;
    else if (m == feb)
        return jan;
    else if (m == mar)
        return feb;
    else if (m == apr)
        return mar;
    else if (m == may)
        return apr;
    else if (m == jun)
        return may;
    else if (m == jul)
        return jun;
    else if (m == aug)
        return jul;
    else if (m == sep)
        return aug;
    else if (m == oct)
        return sep;
    else if (m == nov)
        return oct;
    else
        return nov;
}

int main() {
    enum month m;
    printf("Enter a month(1-12): ");
    scanf("%d", &m);
    printf("%d\n", previous_month(m));
    return 0;
}