program help

[tsjohnsoniii]

I have to write a program that will read in a date in this format (mm/dd/yyyy) and it should output it like this: January 1, 2001. i have most of it done but if i put in a correct month and wrong day it will ask again but it will not detect if there is an incorrect month. How do i get the program to go through all the error checks in the program after i have an incorrect input?

#include <stdio.h>


int main(void)
{
    int month, day, year;
    char * date[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
    printf("Enter a date (mm/dd/yyyy): ");
    scanf("%d/%d/%d", &month, &day, &year);


     if (month <= 0 || month > 12)
    {
        while(month < 0 || month > 12){
        printf("You entered an invalid date. Please try again.\n");
        printf("\nEnter a date (mm/dd/yyyy): ");
        scanf("%d/%d/%d", &month, &day, &year);}
    }else switch (month)
    {
        case 1: case 3: case 5: case 7: case 8: case 10: case 12:
            if (day < 1 || day > 31)
            {
                while(day < 1 || day >31){
                printf("An invalid day was entered. Please try again.\n");
                printf("\nEnter a date (mm/dd/yyyy): ");
                scanf("%d/%d/%d", &month, &day, &year);}
            }
            break;
        case 4: case 6: case 9: case 11:
            if (day < 1 || day > 30)
            {
                while(day < 1 || day > 30){
                printf("An invalid day was entered. Please try again.\n");
                printf("\nEnter a date (mm/dd/yyyy): ");
                scanf("%d/%d/%d", &month, &day, &year);}
            }
            break;
        case 2:
            if(year % 400 == 0 || (year % 100 != 0 && year%4 == 0))
            {
                if (day < 1 || day > 29)
                {
                    while( day < 1 || day > 29){
                    printf("An invalid date was entered. Please try again");
                    printf("\nEnter a date (mm/dd/yyyy): ");
                    scanf("%d/%d/%d", &month, &day, &year);}

                }
            } else if (day < 1 || day > 28)
            {
                while(day < 1 || day > 28){
                printf("An invalid date was entered. Please try again.");
                printf("\nEnter a date (mm/dd/yyyy): ");
                scanf("%d/%d/%d", &month, &day, &year);}

            }
            break;}
    printf("You entered the date %s %d, %d", date[month-1], day, year);


        return 0;

}

[itsme86]

An easy way is with a loop:

int date_is_bad;
do
{
  date_is_bad = 0;
  printf("Enter a date (mm/dd/yyyy): ");
  scanf("%d/%d/%d", &month, &day, &year);

  if(month < 1 || month > 12)
    date_is_bad = 1;
  else
  {
    switch(month)
    {
      ...
    }
  }

  if(date_is_bad)
    puts("An invalid date was entered. Please try again.");
} while(date_is_bad);

[Tclausex]

That's because you reprompt and read a new date, possibly introducing a new error, in the middle of your testing logic. You need to start at the top of your validation for every new date read in.