C++ Temperature program problem

[ElleJay]

My program reads two temperatures from a file, the min and max temperature for each day of a given year.
My problem is to write a function which accepts a year and a month as parameters for example) (2016, 3) (3 means March) and returns the starting location for that month in the arrays which store the temperature values.
The text file has a total of 366 numbers on it.
An example: if the user enters 2016 and 1 for January, the program should return 0 for the location in the array.
I'm not asking to solve, but if someone could help me understand how to create this function, it would be greatly appreciated

[AbstractionAnon]

Have you tried writing some pseudo-code for the problem?

[ElleJay]

It went along the lines of, if user enters '1' for month, then the counter will add 0 to itself and return the index.
If user enters '2', then counter adds 31 to the index (as January has 31 days so it would need to move from index 0 to 30)
Problem is, I don't know how to structure the code for this idea correctly