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// Headers
#include <iostream>
#include <cstdlib>
#include <string>
#include <fstream>
#include <iomanip>
using namespace std;
// Global variables
const string FILENAME = "moviecount.txt";
// Function declarations
int readMovieData(int *& movies, string fileName);
double calculateAverage(int * movies, int size);
double calculateMedian(int * movies, int size);
int* calculateMode(int * movies, int size, int& numModes);
void sort(int *& movies, int size);
int main()
{
int numStudents; // number of students who watch movied
int * movieCounts = nullptr; // an array of integers to store counts of movies for each student
// Read in the movie data
try
{
numStudents = readMovieData(movieCounts, FILENAME);
}
catch (const char * message) // if file cannot be opened then catch the thrown exception
{
cout << message << endl;
system("PAUSE");
exit(EXIT_FAILURE);
}
cout << setprecision(2) << fixed << showpoint; // set decimal places to two for average and median
cout << "Total number of students who watched movies is " << numStudents << endl;
cout << "The average number of movies watched by all students is " << calculateAverage(movieCounts, numStudents) << endl;
cout << "The median number of movies watched by all students is " << calculateMedian(movieCounts, numStudents) << endl;
int numModes = 0; // number of modes in the list, there could be more than one
int * modes = calculateMode(movieCounts, numStudents, numModes); // list of modes is returned and stored in modes
cout << "The mode number of movies watched by all students is ";
if (numModes >= 1)
{
cout << modes + 0; // output the first mode
}
for (int i = 0; i < numModes; i++) // if there is more than one, output the remaining modes
{
cout << ", " << modes + i;
}
cout << endl;
// Make sure we place the end message on a new line
cout << endl;
// The following is system dependent. It will only work on Windows
system("PAUSE");
return 0;
}
int readMovieData(int *& movies, string fileName)
{
ifstream in(FILENAME);
if (!in)
{
throw "file did not open";
}
int count = 0;
in >> count;
if (count == 0)
{
throw "file has no data";
}
movies = new int[count];
for (int i = 0; i < count; ++i)
{
in >> *(movies + i);
}
return count;
}
double calculateAverage(int * movies, int size)
{
double sum = 0;
double average;
for (int i = 0; i < size; ++i)
{
sum += *(movies + i);
}
average = sum / size;
return average;
}
double calculateMedian(int * movies, int size)
{
sort(movies, size);
int median, middle;
middle = size / 2;
//checking if size is even
if (size % 2 == 0)
{
//Calculate the median.
median = (*(movies + middle) + *(movies + middle - 1)) / 2;
}
//size is odd.
else
{
//Calculate the median.
median = *(movies + middle);
}
return median;
}
/***********************************************************
Description
PARAM: movies points to a dynamic array
size is the number of elements in array pointed to by movies
numModes is a reference variable used to return the number of modes found in movies
PRE: movies points to an array of size elements
POST: Each mode value is stored in a dynamic array of integers with size of size
The dynamic array of modes is returned
NOTE: std::fill was used to clear the array when a new mode larger than other modes was found
To make it easier to determine the number of like values, movies is sorted
************************************************************/
int * calculateMode(int * movies, int size, int & numModes)
{
sort(movies,size);
int * modes = new int[size];
int current = 0, count = 0, maxCount = 0;
for (int i = 0; i < size; i++)
{
if (*(movies + i) == *(movies + i + 1)) // check if next is the same number as current aka duplicate
{
count++; //increment current count if duplicate
if (count > maxCount) //check if current count is higher than maxCount
{
maxCount = count; //if current count is higher than maxCount, current count is new maxCount
*(modes + i) = current; //store current number
}
else
{
count = 1; // Reset counter
}
}
}
//Need to also clear modes list when a new mode is found, unless there are multiple modes
return modes;
}
void sort(int *& movies, int size)
{
bool sorted = false;
int *ptr = movies;
while (!sorted)
{
sorted = true;
for (int i = 0; i < size - 1; i++)
{
if (*(ptr + i) > *(ptr + i + 1))
{
int temp = *(ptr + i);
*(ptr + i) = *(ptr + i + 1);
*(ptr + i + 1) = temp;
sorted = false;
}
}
}
}
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