Challenge 40

Description

The purpose of this challenge is to use arrays and functions. This challenge calculates the number of days before and after Christmas.

Requirements

  1. Write a function int date_compare(int month, int day, int anchor_month, int anchor_day) that will return an integer. month and day is compared against anchor_month and anchor_day. The function returns -1 if month and day is before anchor_month and anchor_day, 0 (zero) if they are the same day, and 1 (one) if it is after.
  2. Write a function int days_diff(int m1, int d1, int m2, int d2). 
    int days_diff(int m1, int d1, int m2, int d2)
{
    int days[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
}
  3. The days_diff() function will determine and return the number of days between m1 d1 and m2 d2. Use the array to write an algorithm that will perform this determination.
    1. Always assume that both dates represented by m1 d1 and m2 d2 are within the same year.
    2. Don’t worry about leap years – just assume that February has 28 days.
  4. In main, ask the user to enter two integers to represent month and day
  5. Call days_diff() from main() to determine the number of days between the month and day entered by the user and Christmas day.
  6. In main, call date_compare() function to determine how the entered month and day compares to Christmas (December 25). Use the return value of date_compare() function call to show a message, either “x more days until Christmas” or “It’s Christmas” or “It’s X days after Christmas” where x is the actual number of days returned by days_diff().

DO NOT USE

Any built-in date/time functions

Sample main()

int main()
{
  int month, day;
  int compare, days;

  cout << "Enter month and day: ";
  cin >> month >> day;

  // determine which day is earlier
  compare = date_compare(month, day, 12, 25);

  // determine how many days from (or after) christmas
  days = date_diff(month, day, 12, 25);
  
  // show message
  if (compare == 0)
    cout << "It's Christmas" << endl;
  else if (compare == -1)
    cout << days << " more days until Christmas" << endl;
  else if (compare == 1)
    cout << "It's " << days << " days after Christmas" << endl;
  
  return 0;
}

Sample Interaction / Output

Enter a month and day: 12 24
1 more day until Christmas

[run it again]
Enter a month and day: 12 1 
24 more days until Christmas 

[run it again]
Enter a month and day: 12 25 
It's Christmas!

[run it again] 
Enter a month and day: 12 31 
It's 6 days after Christmas!

[run it again] 
Enter a month and day: 9 30 
86 more days until Christmas!

[run it again] 
Enter a month and day: 1 1 
358 more days until Christmas!

LEGEND
PROGRAM OUTPUT
USER INPUT
FROM INPUT

CATALOG ID: CPP-CHAL0040

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