CS 1320 (Principles of Algorithm Design I):
Homework #3

Assigned:: February 4, 2000.
Due:: February 11, 2000, at start of class.
Credit:: 20 points (10 points per problem).

Instructions

Write a C++ program to solve each of the problems below. Your code should begin with comments that describe what the program is supposed to do, in terms of its inputs and outputs. See the sample programs for examples.

Problems

Temperature conversion

Write a program that defines and tests a function to convert Fahrenheit temperatures to Celsius temperatures. Your program should include:

A function that takes one input parameter, an integer representing a Fahrenheit temperature, and returns an integer representing the equivalent Celsius temperature. Recall from Homework #1 that the rule for converting Fahrenheit temperature F to Celsius temperature C is: C = (5/9)(F - 32) .
A main program -- similar to the one in example program volume.cc -- that first applies the conversion function to a few example inputs and prints the result, and then prompts the user for one more input and prints the results of converting that user-supplied input. The program should print its results in a readable format.

You may want to define additional functions as well. For each function you write, be sure to include comments describing its precondition(s) and postcondition(s).

To help make the results of this conversion more accurate, I have written a function divide_and_round that divides one integer by another and returns a rounded result (rather than the truncated result returned by the integer division operator "/"). To use this function, you will need to:

Copy the file divide.h into your directory. If you are working in the lab, you can do this from Netscape with the "save as" function (available from the "File" menu). If you are working via telnet, you can do this with the following Unix command:
```
	wget http://www.cs.trinity.edu/~bmassing/CS1320_2000spring/Homeworks/HW03/divide.h 
	
```
Include in your program, along with the other lines starting "#include", this line:
```
	#include "divide.h"
	
```
(Notice that here the file name is in quotation marks rather than angle brackets.)

To see how to use the function, read its comments in divide.h.

Income tax estimate

U.S. income tax is a function of taxable income, calculated using a formula such as the following (adapted from the 1999 tax rate schedules for single taxpayers):

If taxable income is not more than $25,750,
tax is 15% of taxable income.
If taxable income is more than $25,750 but not more than $62,450,
tax is $3,863 plus 28% of the amount over $25,750.
If taxable income is more than $62,450 but not more than $130,250,
tax is $14,139 plus 31% of the amount over $62,450.
If taxable income is more than $130,250 but not more than $283,150,
tax is $35,157 plus 36% of the amount over $130,250.
If taxable income is more than $283,150,
tax is $90,201 plus 40% of the amount over $283,150.

Write a program that prompts the user for a taxable income and computes and prints the tax due on that amount, based on the above formula. To do the computation, the program should use a function that takes taxable income (in dollars, i.e., an integer) as a parameter and returns the tax on that amount, also in whole dollars. Round to the nearest dollar. You can do the whole calculation using only integers; you may find the divide_and_round function, discussed in the previous problem, helpful.

What to turn in

Submit your source code as described in the guidelines for programming assignments. For this assignment: