[C++] The code samples show how to read a disk file and skip records until you r

Question

[C++]

The code samples show how to read a disk file and skip records until you reach the location of the records that will contain the values to be used when computing the median value. You can verify that you have the correct results by opening the files with a spreadsheet program (Microsoft Excel, Apple Numbers or OpenOffice Calc), select the column with the balances and compute the median value with one of the statistical functions.

Two data files are provided for this lab. One file has an odd number of records and the other file has an even number of records. You need to run the program for each file and compute the median value for each file.

Sample code is given at the end of this lab assignment. Replace the cout that is inside the while loop with code to compute the total of all balances. After the while loop completes, display the total of all balances.

Balances-1.txt

---------------------------------------------------------

Balances-2.txt

---------------------------------------------------------

Explanation / Answer

The outputs are

Enter the name of the data file: Bal1.txt

There are 117 records in Bal1.txt

The median of Bal1.txt is 1149.42

The total of Bal1.txt is 132927

Enter the name of the data file: Bal2.txt

There are 118 records in Bal2.txt

The median of Bal2.txt is 1146.19

The total of Bal2.txt is 133630

The code for the problem is

#include <iostream>

#include <fstream>

#include <cstdlib> // used by the exit() functiona

using namespace std;

int main(int argc, char* argv[])

{

// variables to control the disk file

ifstream infile;

char filename[200];

int recordCount = 0;

int recordsToSkip = 0;

// variables for fields of each record in the file

int AcctNo = 0;

char Name[100] = "";

double AcctBal = 0.0;

// varible used to determine the median

double median = 0.0;

double total=0;

cout << "Enter the name of the data file: ";

cin >> filename;

// ---- PART 1, Count the number of records in the file

infile.open(filename);

if (infile.fail())

{

cerr << "Unable to open --" << filename << "--, first pass" << endl;

exit(1);

}

while (!infile.eof()) // while not end of file

{

Name[0] = 0; // initialize to 0 to test for empty records/

infile >> AcctNo >> Name >> AcctBal;

if (Name[0] != 0) // ignore empty records

{

recordCount++;

total+=AcctBal;

}

}

infile.close();

cout << "There are " << recordCount << " records in " << filename << endl;

// ---- PART 2, Determine the number of records to skip

if (recordCount %2 == 1)

recordsToSkip = recordCount/2; // Odd number of records

else

recordsToSkip = recordCount/2 - 1; // Even number of records

// ---- PART 3, open the file, skip leading records, determine the mean

infile.open(filename);

while (recordsToSkip>0) // while not end of file

{

Name[0] = 0; // initialize to 0 to test for empty records/

infile >> AcctNo >> Name >> AcctBal;

if (Name[0] != 0)

recordsToSkip--;

}

median=AcctBal;

// - - - - - You need to complete the program

// Display the results

cout << "The median of " << filename << " is " << median << endl << endl;

cout << "The total of " << filename << " is " << total << endl << endl;

return 0;

}

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