Number to Date forumla help

[Grant22]

I need help creating a formula that will return a number 1-12 when the user enters 1-365. The point is to figure out what month a user entered day with fall in. Ex: User enters 1 - January, 32 - Feb, 365 - Dec, etc.

I could go through and code if num >= 1 && num =< 31 then cout << "Jan", etc for every month, but I feel like a formula might be yield a quicker result.

Any help is greatly appreciated.

[Ashishduh]

There really is no formula for this because of the randomness of days per month. If every month had exactly 30 days then you could do this:

#include <math.h> //so that you can use the ceil function
int day;
float month;

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

month = ceil( (float)day / 30); 

[Peter87]

If you don't want to use a lot of if statements you could store the number of days for each month in an array and use that to calculate the correct month.

[Grant22]

I like the idea Peter. But I couldn't get it to work so far. Why isn't the int result adding the total of each array subscript as it steps through?

int main()
{
int NumberOfDays;
const int NUMBER_OF_MONTHS = 12;
int result = 0;
int monthDays[NUMBER_OF_MONTHS] = {31, 28, 31,30, 31, 30, 31, 31, 30, 31, 30, 31};

cout << "Enter a number between 1-365 and I will tell you " << endl;
cout << "the month: ";
cin >> NumberOfDays;
cout << endl;

for (int count = 0; count < NUMBER_OF_MONTHS; count++)
{
if (NumberOfDays > monthDays[count])
result = NumberOfDays - monthDays[count];
else if (NumberOfDays < monthDays[count])
break;
}

cout << result;
system("PAUSE");
return(0);
}

[Grant22]

Nevermind, I just got it. Thanks for the idea!!