HW 5 - Useful Functions

HW 5 – Useful Functions

Due Monday, Feb. 26 at 3:30 PM

Functions are useful things partially because they can be reused. You’ve already reused the GetInteger function by copy-pasting it into a new program, but this week we’re going to improve on that technique.

Your assignment is to produce a header file and implementation file for a bunch of useful functions, and write a sample program that utilizes the functions. The header file (named something like “useful.h”) will be mostly comments. It will contain a prototype for each function, along with the function’s description, preconditions, postconditions, and list of libraries and namespace pieces that it needs.

Here’s an example of a header file – it only includes GetInteger.

// Filename: useful.h
//
// int GetInteger(char* prompt, int min = INT_MIN, int max = //INT_MAX)
// Libraries Used: iostream, cassert, climits
// Using: std::cin, std::cout, std::endl,
// Accepts the following parameters: prompt (a string that asks the user 
//   for input), min  (the minimum acceptable return value, and max (the 
//   maximum acceptable return value).
// Preconditions: min < max
// Postconditions: Returns an integer between min and max, inclusively, 
//   as entered by the user.
//
//(other function descriptions here)

#ifndef USEFUL_H
#define USEFUL_H

#include <climits>

namespace aer	//you must define your own namespace
{
	int GetInteger(const char* prompt, int min = INT_MIN, int max = INT_MAX);

	//(other function prototypes here)
}

#endif

The implementation file should just have the function definitions. Example:

// Filename: useful.cpp
// Function definitions

#include <iostream>
#include <cassert>
#include <climits>

using std::cin;
using std::cout;
using std::endl;

#include "useful.h"

namespace aer{

int GetInteger(const char* prompt, int min, int max)
{
    //you have this code
}

//more function definitions go here

}//end namespace

Requirements

You must include the following functions:

GetInteger – with default parameters
GetDouble – overloaded: one version with limits and one without
GetChar
Ask – this is a function that will ask the user a yes-or-no question and return a boolean value determined by their answer
DisplayMoney – accepts a double representing a dollar amount, outputs it in the form $***12.00
Distance – calculates the distance between two points (Cartesian coordinates)
Swap – this will be a template function which swaps the values in two memory locations

You must write pre- and post-conditions for all the functions. Full error-checking is necessary (use assert for non-input functions).

Your sample program should use all the functions – see how many functions you can use at once. (That is, don’t have an enormous menu asking which function you want to test – combine tasks.)

A design document is not required for this assignment; the comments in the header file will serve this purpose. Don’t forget to turn in all your code as well as your executable and sample output.

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