c11p11.c

//Given the definition of a date structure as defined
//in this chapter, write a function called dateUpdate that
//takes a pointer to a date structure as its argument and
//that updates the structure to the following day
#include<stdio.h>
#include<stdbool.h>
struct date
{
  int day;
  int month;
  int year;
};
int numberOfDays(struct date *d);
bool isLeapYear(struct date *d);
struct date dateUpdate(struct date *d);
int main(void)
{
  struct date today,nextDay;
  struct date *todayPtr;
  todayPtr=&today;
  printf("enter today's date (MM DD YYYY): ");
  scanf("%i %i %i",&today.month,&today.day,&today.year);
  nextDay=dateUpdate(todayPtr);
  printf("Tomorrow's date is %d/%d/%d \n",nextDay.month,nextDay.day,nextDay.year);
  return 0;
}
struct date dateUpdate(struct date *today)
{
  struct date tomorrow;
  if(today->day!=numberOfDays(today))
    {
      tomorrow.day=today->day+1;
      tomorrow.month=today->month;
      tomorrow.year=today->year;
    }
  else if(today->month==12)
  {
    tomorrow.day=1;
    tomorrow.month=1;
    tomorrow.year=today->year+1;
  }
  else
  {
    tomorrow.day=1;
    tomorrow.month=today->month+1;
    tomorrow.year=today->year;
  }
  return tomorrow;
}
int numberOfDays(struct date *d)
{
  const int daysPerMonth[12]={31,28,31,30,31,30,31,31,30,31,30,31};
  int days;
  if(isLeapYear(d)==true && d->month==2)
    days=29;
  else
    days=daysPerMonth[d->month-1];
  return days;
}
bool isLeapYear(struct date *d)
{
  bool leap;
  if((d->year%4==0 && d->year%100!=0)||d->year%400==0)
    leap=true;
  else
    leap=false;
  return leap;
}