Wuts good board?? I am a undergrad student that is taking c++ for my major. I am an electrical engineering major. This is my first time ever coming in contact with programming, the shit is so hard. Each time i sit down and try to read it, it look so crazy to me, i have this program due

The program displays the total income taxes that you must pay for 2005 or your refund in 2005 is determined as follows:
Let total_tax = amount of taxes owed (you will calculate total_tax = federal tax + state tax + city tax).
If total_tax is greater than the total amount of tax already taken from your salary (you will find these amounts from your input data), then you must pay additional taxes of total_tax minus the taxes already taken from your salary.
If total_tax is less than the total amount of tax already taken from your salary then you will receive a refund equal to the difference between the taxes already taken from your salary and total_tax.
Federal tax = 15.7% of your taxable income that is <= $25,000 + 25% of any of your taxable income above $25,000
where:
taxable income = gross salary - (no. of dependents * $1,000) - (no. of deductions * $475)
State tax = 10.3% of Federal tax unless Federal tax < $200 then State tax = 0.
City Tax = 8.5% of State tax unless State tax <= $100 then City tax = 0.
Input: the input data stream format is:
type of datum meaning
characters year (2005)
characters social security number (9 characters)
float gross salary
float federal tax already taken from salary
float state tax already taken from salary
float city tax already taken from salary
integer number of dependents
integer number of deductions
Create an external file named tax.txt. Name your input file taxdata and include the following statement in your program: taxdata.open(“tax.txt”);.
Run your program twice, first with the following input data:
2005 949581726 26000.00 5000.00 495.00 258.00 4 6
and then with a set of your own data.

I started the program, and i did the calculations by hand, but wut stumps me is the input file and the then if, how would i do the input file?? how do i put the # into the file correctly so that the program reads it correctly?? how would i incorporate the then if statment in my calculations? and how would i stop the user from using it if they put in a number that makes the value untrue? Please help i would greatly appreciate it thanks guys!!