looping problem

I have created two functions one to test if a year is a leap year and another to test for a valid day and month and the code works perfectly. But im having a problem if the date is wrong I want the user to keep entering data until they enter the correct date and if they enter the correct date I want the information stored in the struct. Currently the while loop keeps looping if the date is correct or wrong. The if statement (if (CAPACITY < count)) allows a user to enter one item at a time. Can someone help?

Code:

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

#define  bool int
#define YES 1
#define NO 0
#define CAPACITY 20
#define SIZE 50
#define TRUE 1
#define FALSE 0


typedef struct
{
	int day;
	int month;
	int year;
}Date;

typedef struct
{
	char name[SIZE];
	Date dob;
}Student;

void checkDate(Student data[], int count);
bool isLeapYear(int year);

int main (void)
{
	bool  check = FALSE;
	int i, count = 0;
	Student database[CAPACITY];


			 if (CAPACITY > count)
				{
					while(check == FALSE)
					{
						printf("Please enter a person's first name, lastname and date of birth\n");
					scanf("%s %s %d %d %d", database[count].name, &database[count].dob.day, &database[count].dob.month, &database[count].dob.year);
				
					
					checkDate(database, count);

					}/*end while(check == FALSE) */
					
					count++;
				 
				}/*end if (CAPACITY > count) */
						else
						{
							printf("The database is full\n");
						}
				
	return 0;
}/*end main() function */


/***************************************************************************/
/*Function to check valid date                                             */
/***************************************************************************/
void checkDate(Student data[], int count)
{
	int monthLength[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
	bool check = FALSE;	

	/*Add 29 days to Feburary if year is a leap year*/
	if (isLeapYear(data[count].dob.year))
	{
		monthLength[2] = 29;
	}

	/*If month entered is less then one and greater than 12 print error message*/
	if (data[count].dob.month < 1 || data[count].dob.month > 12)
	{
		printf("Invalid month\n");
		check = FALSE;
	}
	/*If day entered is less then 1 and greater then month number in the array month_length print error message*/
	else if (data[count].dob.day < 1 || data[count].dob.day > monthLength[data[count].dob.month])
	{
		printf("Invalid day\n");
		check = FALSE;
	}

}/* end bool checkDate(Student data[], int count) */

/***************************************************************************/
/*Function to check if a year is a leap year                               */
/***************************************************************************/
bool isLeapYear(int year)
{
	bool valid;

	if ((year%4) !=0)
	{
		valid = NO;
	}
	else if ((year%400) == 0)
	{
		valid = YES;
	}
	else if ((year%100) == 0)
	{
		valid = NO;
	}
	else
	{
		valid = YES;
	}

	return (valid);
}/*end bool isLeapYear(int year) */

I have a few comments. don't you have like std_bool for a header or something like that?
What is the significant difference between the TRUE and FALSE and YES and NO macros?

Don't use scanf to do all the work. Read in a string with fgets and parse that instead.

As far as I know, leap years divide by four evenly. Your isLeapYear function does way too much work, and it also returns a void, when you say it should return a bool. No wonder you loop forever, the variable check is never updated.

>>Your isLeapYear function does way too much work

No its not, read this

[edit]
that leap year code was wrong - sorry guys.
[/edit]

Your primary problem with that loop is that check variable is
never updated as citizen said - your checkDate function is going
to have to return a value. Also, when you fix that issue, you'll
notice that the program will terminate after entering only 1 value -
change

Code:

if (CAPACITY > count)

/*to*/

while (CAPACITY > count)

and remove the corresponding else statement:

Code:

else
{
        printf("The database is full\n");
}

/*to just*/

        printf("The database is full\n");

Interestingly enough, there is an official comp.lang.c FAQ entry which also might shed some additional light on the matter of leap years with regard to coding such a test in C.

Use a lookup table.


Quzah.

Originally Posted by quzah

Use a lookup table.


Quzah.

For determining leap years, you mean?

Definately.


Quzah.

You know, I was just reading a post on this subject where one of our members implemented the leap year check with a function macro - yet another way of doing it. This sort of question comes up enough every year, it would almost be cool to have a few of these different ideas examined in a separate board FAQ with a smidge of code to demonstrate the various methods of achieving the same end, with some discussion on the pros and cons of each.

I have updated the code to bool like you said and return check but the loop still does not break.

Code:

bool checkDate(Student data[], int count)
{
	int monthLength[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
	bool check = FALSE;	

	/*Add 29 days to Feburary if year is a leap year*/
	if (isLeapYear(data[count].dob.year))
	{
		monthLength[2] = 29;
	}

	/*If month entered is less then one and greater than 12 print error message*/
	if (data[count].dob.month < 1 || data[count].dob.month > 12)
	{
		printf("Invalid month\n");
		check = FALSE;
	}
	/*If day entered is less then 1 and greater then month number in the array month_length print error message*/
	else if (data[count].dob.day < 1 || data[count].dob.day > monthLength[data[count].dob.month])
	{
		printf("Invalid day\n");
		check = FALSE;
	}
         else
        {
              check = TRUE;
        }
return check;

}/* end bool checkDate(Student data[], int count) */

In main:

Code:

check = checkDate(database, count);

Thanks very much citizen you solved my problem and thank you everyone else for your help and advice also