/* Drop Lowest Score - This program dynamically allocates an array large
enough to hold a user-defined number of test scores. Once all scores
are entered, the array is passed to a function that sorts them in
ascending order.
Another function is called that calculates the average score. The
p rogram displays the sorted list of scores and averages with
appropriate headings. Pointer notation is used rather than array
notation whenever possible.
Input Validation: No negative numbers for test scores is accepted.
This is a modification of Programming Challenge 2. The lowest score
entered by the user is detected and removed, before the scores are
sorted, and the average is calculated. */
#include "Utility.h"
/* Function prototypes */
void mainMenu();
void displayIntro();
void displayMenuItems();
void getTestScores(double *, const int);
int dropLowestScore(double *, int);
void sortScores(double *, const int);
double calcAverage(double *, const int);
void displayResults(const double *, const double, const int);
int main()
{
mainMenu();
pauseSystem();
return 0;
}
/* **********************************************************
Definition: mainMenu
Allows the user to select from the following items:
* View Introduction
* Enter Test-Scores
* View Score-Data
* Quit
It takes care of calling the necessary functions, passing
and receiving results, and freeing up the memory when the
user decides to quit the program.
********************************************************** */
void mainMenu()
{
/* Dynamically allocated array */
double *testScores = nullptr;
const int DISPLAY_INTRODUCTION = 1,
GET_TEST_SCORES = 2,
VIEW_RESULTS = 3,
QUIT = 4;
int menuItem = 0,
numScores = 0;
double averageScore = 0.0;
do
{
displayMenuItems();
cin >> menuItem;
/* Validate input */
while (menuItem < DISPLAY_INTRODUCTION || menuItem > QUIT)
{
cout << "\n\tInvalid menu item selected!\n"
<< "\tYour choice: ";
cin >> menuItem;
}
switch (menuItem)
{
case DISPLAY_INTRODUCTION:
{
displayIntro();
}
break;
case GET_TEST_SCORES:
{
/* Get the number of scores (at least three) */
cout << "\n\tHow many test-scores do you wish to enter?\n"
<< "\t(3 and above): ";
cin >> numScores;
cout << "\n";
/* Input validation */
while (numScores < 3)
{
cout << "\tInvalid input!\n"
<< "\tHow many test-scores do you wish to enter? ";
cin >> numScores;
cout << "\n";
}
/* Dynamically allocates the array to hold the number of
test scores the user wishes to enter */
testScores = new double[numScores];
/* Gets the number of scores entered by the user */
getTestScores(testScores, numScores);
/* Sorts the scores with an ascending-order selection sort
algorithm */
sortScores(testScores, numScores);
/* Gets the new number of elements contained in the array,
finds and drops the lowest score */
numScores = dropLowestScore(testScores, numScores);
/* Sorts testScores once more after the lowest score has
been dropped */
sortScores(testScores, numScores);
/* Calculates the average score and returns the result */
averageScore = calcAverage(testScores, numScores);
}
break;
case VIEW_RESULTS:
{
/* Displays the data after sorting the scores and
calculating the average */
displayResults(testScores, averageScore, numScores);
}
break;
case QUIT:
{
cout << "\n\tDoing a little housekeeping ... ";
/* Free up memory */
delete[] testScores;
testScores = nullptr;
cout << "\n\ttestScores cleared: " << testScores
<< "\n\tPress enter to close this window!\n";
}
break;
}
} while (menuItem != QUIT);
}
/* **********************************************************
Definition: displayMenuItems
This function displays the menu items the user can select
between.
********************************************************** */
void displayMenuItems()
{
cout << "\n\n\t\tAVERAGE TEST SCORE CALCULATOR\n\n"
<< "\t1. View Introduction\n"
<< "\t2. Enter Test-Scores\n"
<< "\t3. View Score-Data\n"
<< "\t4. Quit\n\n"
<< "\tYour choice: ";
}
/* **********************************************************
Definition: displayIntroduction
This function introduces the program and how it works to
the user.
********************************************************** */
void displayIntro()
{
cout << "\n\n\t\tAVERAGE TEST SCORE CALCULATOR\n\n"
<< "\tThis program allows you to enter a number of scores to\n"
<< "\tbe averaged. The number of scores to be entered has to\n"
<< "\tbe at least 3.\n\n"
<< "\tAfter the scores have been sorted in ascending order, the\n"
<< "\tthe lowest of all scores is dropped, and the average score\n"
<< "\twill be calculated. Having finished entering your scores,\n"
<< "\tyou can choose option '3' in the menu to view the scores in\n"
<< "\tsorted order and the average score that has been calculated.\n\n";
}
/* **********************************************************
Definition: getTestScores
This function accepts testScores and numScores, containing
the number of elements to be stored in the array, as its
arguments. It gets the scores to be stored by way of input
from the user.
********************************************************** */
void getTestScores(double *testScores, const int numScores)
{
for (int index = 0; index < numScores; index++)
{
cout << "\tScore #" << (index + 1) << ": ";
cin >> *(testScores + index);
/* Validate Input */
while ((*(testScores + index) <= 0) ||
(*(testScores + index) > 100.0))
{
cout << "\n\t\tYou entered an invalid score!\n\n";
cout << "\tScore #" << (index + 1) << ": ";
cin >> *(testScores + index);
}
}
cout << "\n";
}
/* **********************************************************
Definition: dropLowestScore
This function accepts testScores and numScores as its
arguments, containing the number of elements in the array.
It drops the lowest score and returns the new number of
elements indicated by numScores. The fact that the lowest
score is already placed at subscript position 0 after
sorting is used to advantage here.
********************************************************** */
int dropLowestScore(double *testScores, int numScores)
{
int index = 0;
numScores--;
*(testScores + index) = *(testScores + numScores);
return numScores;
}
/* **********************************************************
Definition: sortScores
This function accepts testScores and numScores, containing
the number of elements stored in the array, as arguments.
An ascending-order selection sort is performed on the
elements stored in the array.
********************************************************** */
void sortScores(double *testScores, const int numScores)
{
int startScan = 0,
minIndex = 0,
index = 0;
double minElem = 0.0;
for (startScan = 0; startScan < (numScores - 1); startScan++)
{
minIndex = startScan;
minElem = *(testScores + startScan);
for (index = startScan + 1; index < numScores; index++)
{
if (*(testScores + index) < minElem)
{
minElem = *(testScores + index);
minIndex = index;
}
}
*(testScores + minIndex) = *(testScores + startScan);
*(testScores + startScan) = minElem;
}
}
/* **********************************************************
Definition: calcAverage
This function accepts testScores and numScores as its
argument. It steps through the array to total the scores,
then calculates and returns the average.
********************************************************** */
double calcAverage(double *testScores, const int numScores)
{
double total = 0.0,
average = 0.0;
for (int count = 0; count < numScores; count++)
{
total += *(testScores + count);
}
/* Calculates and returns the average */
return average = total / numScores;
}
/* **********************************************************
Definition: displayResults
This function accepts testScores, averageScore and
numScores as its argument. It displays the scores in
sorted order and the average score.
********************************************************** */
void displayResults(const double *testScores, const double averageScore,
const int numScores)
{
int index = 0;
cout << fixed << showpoint << setprecision(2);
cout << "\n\n\tTHE SCORES IN SORTED ORDER\n";
for (index = 0; index < numScores; index++)
{
cout << "\n\t\tSCORE #" << (index + 1) << ":\t"
<< setw(5) << right << *(testScores + index)
<< " ";
}
cout << "\n\t-------------\n"
<< "\tAVERAGE SCORE:\t\t" << averageScore << "\n";
}
Example Output:
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