Question

(C++ programming) Need help with homework.

Write a program that can be used to gather statistical data about the number of hours per week college students play video games. The program should perform the following steps:

1). Read data from the input file into a dynamically allocated array. The first number in the input file, n, represents the number of students that were surveyed. First read this number then use it to dynamically allocate an array of n integers. On the next n lines, there is an integer representing the number of hours per week each student played video games. Here is an example:

5 // There are 5 students

9 // 9 hours per week – student 1

4 // 4 hours per week – student 2

10 // 10 hours per week – student 3

4 // 4 hours per week – student 4

7 // 7 hours per week – student 5 Read the rest of the numbers from the file into the dynamically allocated array.

2). Sort the array in ascending order: 4 4 7 9 10
3). Write the sorted array to a file, one number per line, including the number of students on the first line (same format as the input file)

4). Calculate the average of the numbers in the array without the lowest and the highest values: (4 + 7 + 9) / 3 = 6.6 5). Display the number of students, the average, the lowest and highest values in a readable format of your choice (screen output).

6). Finally, release the memory and terminate the program.
Run the program using the following input files: 1. Input file name: videogamesurvey.txt 2. Input file name: gamestats.txt 3. Input file name: survey.txt

These are all function prototypes:

// Function prototypes
int *readSurveyData(string filename, int &n);
void insertionSort(int *pAry, int *pLast);
void writeArray(int *pAry, int *pLast);
void writeArray(string filename, int *pAry, int *pLast);
double calcAvg(int *pAry, int *pLast);
void displayStats(int n, double avg, int smallest, int largest);

Thank You.

Answer 1

If you have any doubts, please give me comment...

#include <iostream>

#include <fstream>

#include <string>

using namespace std;

int *readSurveyData(string filename, int &n);

void insertionSort(int *pAry, int *pLast);

void writeArray(int *pAry, int *pLast);

void writeArray(string filename, int *pAry, int *pLast);

double calcAvg(int *pAry, int *pLast);

void displayStats(int n, double avg, int smallest, int largest);

int main()

{

    string filename;

    int *data;

    int num_studs;

    cout << "Input filename: ";

    cin >> filename;

    data = readSurveyData(filename, num_studs);

    insertionSort(data, data + num_studs);

    writeArray(filename, data, data + num_studs);

    cout<<"Data from File: "<<endl;

    writeArray(data, data + num_studs);

    double avg = calcAvg(data, data + num_studs);

    displayStats(num_studs, avg, *data, *(data + num_studs-1));

    delete[] data;

    return 0;

}

int *readSurveyData(string filename, int &n)

{

    ifstream inFile;

    inFile.open(filename.c_str());

    if (inFile.fail())

    {

        cout << "Unable to open file" << endl;

        return NULL;

    }

    inFile >> n;

    int *data = new int[n];

    for (int i = 0; i < n; i++)

    {

        inFile >> data[i];

    }

    inFile.close();

    return data;

}

void insertionSort(int *pAry, int *pLast)

{

    int i = 1, key, j;

    while ((pAry + i) < pLast)

    {

        key = *(pAry + i);

        j = i - 1;

        while (j >= 0 && *(pAry + j) > key)

        {

            *(pAry + j + 1) = *(pAry + j);

            j = j - 1;

        }

        *(pAry + j + 1) = key;

        i++;

    }

}

void writeArray(int *pAry, int *pLast)

{

    cout<<"Number of Students: "<<(pLast-pAry)<<endl;

    int i=0;

    while((pAry+i)<pLast){

        cout<<"Student "<<(i+1)<<": "<<*(pAry+i)<<endl;

        i++;

    }

}

void writeArray(string filename, int *pAry, int *pLast)

{

    ofstream outFile;

    outFile.open(filename.c_str());

    outFile<<(pLast-pAry)<<endl;

    int i=0;

    while((pAry+i)<pLast){

        outFile<<*(pAry+i)<<endl;

        i++;

    }

    outFile.close();

}

double calcAvg(int *pAry, int *pLast)

{

    int i=1;

    int sum = 0;

    while((pAry+i)<pLast-1){

        sum += *(pAry+i);

        i++;

    }

    return (double)sum/(i-1);

}

void displayStats(int n, double avg, int smallest, int largest)

{

    cout<<"\nStats: "<<endl;

    cout<<"Number of Students: "<<n<<endl;

    cout<<"Average: "<<avg<<endl;

    cout<<"Smallest: "<<smallest<<endl;

    cout<<"Largest: "<<largest<<endl;

}