Question

This program has an array of floating point numbers as a private data member of a class. The data file contains floating point temperatures which are read by a member function of the class and stored in the array.

Exercise 1: Why does the member function printList have a const after its name but getList does not?

Exercise 2: Fill in the code so that the program reads in the data values from the temperature file and prints them to the screen with the following output:

78.90

87.40

60.80

70.40

75.60

Exercise 3: Add code (member function, call and function implementation) to print the average of the numbers to the screen so that the output will look like the output from Exercise 2 plus the following:

The average temperature is 74.62

the code is as follows:

// This program reads floating point data from a data file and places those

// values into the private data member called values (a floating point array)

// of the FloatList class. Those values are then printed to the screen.

// The input is done by a member function called GetList. The output

// is done by a member function called PrintList. The amount of data read in

// is stored in the private data member called length. The member function

// GetList is called first so that length can be initialized to zero.

// PLACE YOUR NAME HERE

#include <iostream>

#include <fstream>

#include <iomanip>

using namespace std;

const int MAX_LENGTH = 50; // MAX_LENGTH contains the maximum length of our list

class FloatList // Declares a class that contains an array of

// floating point numbers

{

public:

void getList(ifstream&); // Member function that gets data from a file

void printList() const; // Member function that prints data from that

// file to the screen.

FloatList(); // constructor that sets length to 0.

~FloatList(); // destructor

private:

int length; // Holds the number of elements in the array

float values[MAX_LENGTH]; // The array of values

};

int main()

{

ifstream tempData; // Defines a data file

// Fill in the code to define an object called list of the class FloatList

cout << fixed << showpoint;

cout << setprecision(2);

tempData.open("temperatures.txt");

// Fill in the code that calls the getList function.

// Fill in the code that calls the printList function.

return 0;

}

FloatList::FloatList()

{

// Fill in the code to complete this constructor that

// sets the private data member length to 0

}

// Fill in the entire code for the getList function

// The getList function reads the data values from a data file

// into the values array of the class FloatList

// Fill in the entire code for the printList function

// The printList function prints to the screen the data in

// the values array of the class FloatList

Answer 1

Given below is the code for the question.
Please do rate the answer if it was helpful. Thank you

// This program reads floating point data from a data file and places those
// values into the private data member called values (a floating point array)
// of the FloatList class. Those values are then printed to the screen.
// The input is done by a member function called GetList. The output
// is done by a member function called PrintList. The amount of data read in
// is stored in the private data member called length. The member function
// GetList is called first so that length can be initialized to zero.
// PLACE YOUR NAME HERE

#include <iostream>

#include <fstream>

#include <iomanip>

using namespace std;

const int MAX_LENGTH = 50; // MAX_LENGTH contains the maximum length of our list

class FloatList // Declares a class that contains an array of

// floating point numbers

{

public:

void getList(ifstream&); // Member function that gets data from a file

void printList() const; // Member function that prints data from that

// file to the screen.

float average() const; //Member function to get the average of data

FloatList(); // constructor that sets length to 0.

~FloatList(); // destructor

private:

int length; // Holds the number of elements in the array

float values[MAX_LENGTH]; // The array of values

};

int main()

{

ifstream tempData; // Defines a data file

// Fill in the code to define an object called list of the class FloatList
FloatList list;

cout << fixed << showpoint;

cout << setprecision(2);

tempData.open("temperatures.txt");

// Fill in the code that calls the getList function.
list.getList(tempData);

// Fill in the code that calls the printList function.
list.printList();

return 0;

}

FloatList::FloatList()

{

// Fill in the code to complete this constructor that
// sets the private data member length to 0
length = 0;

}

// Fill in the entire code for the getList function
// The getList function reads the data values from a data file
// into the values array of the class FloatList

void FloatList::getList(std::ifstream &in)
{
if(!in.is_open()){
cout << "ERROR: could not read input file" << endl;
return;
}

while(in >> values[length])
length++;

in.close();
}

// Fill in the entire code for the printList function
// The printList function prints to the screen the data in
// the values array of the class FloatList
void FloatList::printList() const
{

for(int i = 0; i < length; i++){
cout << values[i] << endl;
}
cout << "The average temperature is " << average() << endl;
}

float FloatList::average() const{
float avg = 0;
for(int i = 0; i < length; i++){
avg += values[i];
}
return avg/length;
}

FloatList::~FloatList(){
}

input file: temperatures.txt
==============
78.90
87.40
60.80
70.40
75.60

output
====
78.90
87.40
60.80
70.40
75.60
The average temperature is 74.62