Question

Can someone please help? Thanks in advance!

Simple Vector Modification C++ Your program Assignment Modify the Simple Vector class template presented in this Chapter 16-11) to include the member functions push_back and pop_back. First the User will enter the numbers that are to be in the array. The push_back function should accept an argument and insert its value at the end of the array that has been created. The pop_back function should accept no argument and remove the last element from the array. Use this created program to text the class.

Example Enter number of elements to put in a vector (between 2 and 20): 8 A vector of integers will be created first Vector created : The contents of the array are: 0 13 2 30 36 25 120 126 Enter a whole number to insert at the end of the vector (decimal values will be rounded down): 6 calling push_back function to insert the value The new vector values are: 13 2 30 36 25 120 126 6 Now calling pop_back function to remove the last added value The new vector values are: @ 13 2 30 36 25 120 126 Exercise will be repeated with decimal values now Enter number of elements to put in a vector (between 2 and 20): 6 A vector of decimals will be created first vector created: The contents of the array are: @ 4 2.8 0.6 12.8 19 Enter a decimal number to insert at the end of the vector: 5.5 Calling push_back function to insert the value The new vector values are: @ 4 2.8 0.6 12.8 19 5.5 Now calling pop_back function to remove the last added value The new vector values are: @ 4 2.8 0.6 12.8 19 Would you like to repeat (y/n)?: What the Visual Studio Solution File can look like Solution 'Simple Vector Modificatgion_19' (1 of 1 project) $ Simple Vector Modificatgion_19 - References External Dependencies Header Files SimpleVector.h Resource Files Source Files ++ Simple Vector Modificatgion_19.cpp

Answer 1

#include <iostream>

using namespace std;

template < class T >
  class SimpleVector {
    private:
      T * aptr; // To point to the allocated array
    int arraySize; // Number of elements in the array
    void memError(); // Handles memory allocation errors
    void subError(); // Handles subscripts out of range

    public:
      SimpleVector() {
        aptr = 0;
        arraySize = 0;
      }
    SimpleVector(int);
    SimpleVector(const SimpleVector & );
    ~SimpleVector();
    int size() const {
      return arraySize;
    }
    T getElementAt(int position); // return a specific element
    T & operator[](const int & );
    void pushBack(const T & newItem);
    void popBack();
  };

template < class T >
  SimpleVector < T > ::SimpleVector(int s) {
    arraySize = s;
    // Allocate memory for the array.
    try {
      aptr = new T[s];
    } catch (bad_alloc) {
      memError();
    }

    // Initialize the array.
    for (int count = 0; count < arraySize; count++)
      *
      (aptr + count) = 0;
  }

template < class T >
  SimpleVector < T > ::SimpleVector(const SimpleVector & obj) {
    // Copy the array size.
    arraySize = obj.arraySize;
    // Allocate memory for the array.
    aptr = new T[arraySize];
    if (aptr == 0)
      memError();

    // Copy the elements of obj's array.
    for (int count = 0; count < arraySize; count++)
      *
      (aptr + count) = * (obj.aptr + count);
  }

template < class T >
  SimpleVector < T > ::~SimpleVector() {
    if (arraySize > 0)
      delete[] aptr;
  }

template < class T >
  void SimpleVector < T > ::memError() {
    cout << "ERROR:Cannot allocate memory.\n";
    exit(EXIT_FAILURE);
  }

template < class T >
  void SimpleVector < T > ::subError() {
    cout << "ERROR: Subscript out of range.\n";
    exit(EXIT_FAILURE);
  }

template < class T >
  T SimpleVector < T > ::getElementAt(int sub) {
    if (sub < 0 || sub >= arraySize)
      subError();
    return aptr[sub];
  }

// Overloaded [] operator. The argument is a subscript. *
// This function returns a reference to the element *
// in the array indexed by the subscript. *

template < class T >
  T & SimpleVector < T > ::operator[](const int & sub) {
    if (sub < 0 || sub >= arraySize)
      subError();
    return aptr[sub];
  }

//Appends a new element increasing vector's size by 1
template < class T >
  void SimpleVector < T > ::pushBack(const T & newItem) {
    //allocate a new array of current size + 1
    int newSize = arraySize + 1;
    T * newArr = new T[newSize];

    //copy existing elements
    for (int count = 0; count < arraySize; count++)
      *
      (newArr + count) = * (aptr + count);
    //add the new element
    *(newArr + newSize - 1) = newItem;

    //destroy old array
    delete[] aptr;

    //store new info in instance fields
    aptr = newArr;
    arraySize = newSize;
  }

// Removes vector's last element & reducing vector's size by 1
template < class T >
  void SimpleVector < T > ::popBack() {
    //allocate a new array of current size - 1
    int newSize = arraySize - 1;
    T * newArr = new T[newSize];

    //copy existing elements
    for (int count = 0; count < arraySize - 1; count++)
      *
      (newArr + count) = * (aptr + count);

    //destroy old array
    delete[] aptr;

    //store new info in instance fields
    aptr = newArr;
    arraySize = newSize;
  }

int main() {
  SimpleVector < int > intTable;
  SimpleVector < double > doubleTable;

  // push_back
  cout << "\nUsing push_back() to populate.\n" << endl;
  for (double num = 1.1; num < 5; num += 1.1) {
    intTable.pushBack((int) num);
    doubleTable.pushBack(num);
  }
  // Display
  cout << "intTable contains:\n";
  for (int count = 0; count < intTable.size(); count++)
    cout << intTable[count] << " ";
  cout << endl;

  cout << "doubleTable contains:\n";
  for (int count = 0; count < doubleTable.size(); count++)
    cout << doubleTable[count] << " ";
  cout << endl;

  // pop_back
  cout << "\nUsing pop_back() to remove the last item.\n" << endl;
  intTable.popBack();
  doubleTable.popBack();

  // Display
  cout << "intTable contains:\n";
  for (int count = 0; count < intTable.size(); count++)
    cout << intTable[count] << " ";
  cout << endl;

  cout << "doubleTable contains:\n";
  for (int count = 0; count < doubleTable.size(); count++)
    cout << doubleTable[count] << " ";
  cout << endl;

  //hold screen
  cout << endl << "Press Enter to quit." << endl;
  cin.get();

  return 0;
}