How everyone, I have a problem that's rather ambiguous. I think it's ambiguous in the sense that it is given by my instructor as it is without further explanation. I have created a simple vector class that stimulates vectors. On this basis, I am to further refine and add in new functionalities. According to my instructor: Use a simple vector you created before to create two other more complex vectors with
1) Memory allocation that doubles the size of memory when end reached, and 1/2's memory when the size reaches 1/4.
2) Implemented with a singularly linked list.
That's literally all I have to begin with. I am fairly new to coding. On this note, I am having a hard time approaching this problem, either because the instruction is insufficient, or I haven't gotten familiar enough with c++. Could someone pls give me some pointers on how to approach this problem? (What the hell am I supposed to do?) Any suggestions are greatly appreciated:)
Here's the vector class that I created:
SimpleVector.h:
#ifndef SIMPLEVECTOR_H
#define SIMPLEVECTOR_H
#include <iostream>
#include <new> // Needed for bad_alloc exception
#include <cstdlib> // Needed for the exit function
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:
// Default constructor
SimpleVector()
{ aptr = 0; arraySize = 0;}
// Constructor declaration
SimpleVector(int);
// Copy constructor declaration
SimpleVector(const SimpleVector &);
// Destructor declaration
~SimpleVector();
// Accessor to return the array size
int size() const
{ return arraySize; }
// Accessor to return a specific element
T getElementAt(int position);
// Overloaded [] operator declaration
T &operator[](const int &);
void push_back(T);
T pop_back();
void push_front(T);
T pop_front();
};
//***********************************************************
// Constructor for SimpleVector class. Sets the size of the *
// array and allocates memory for it. *
//***********************************************************
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;
}
//*******************************************
// Copy Constructor for SimpleVector class. *
//*******************************************
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);
}
//**************************************
// Destructor for SimpleVector class. *
//**************************************
template <class T>
SimpleVector<T>::~SimpleVector()
{
if (arraySize > 0)
delete [] aptr;
}
//*******************************************************
// memError function. Displays an error message and *
// terminates the program when memory allocation fails. *
//*******************************************************
template <class T>
void SimpleVector<T>::memError()
{
cout << "ERROR:Cannot allocate memory.\n";
exit(EXIT_FAILURE);
}
//***********************************************************
// subError function. Displays an error message and *
// terminates the program when a subscript is out of range. *
//***********************************************************
template <class T>
void SimpleVector<T>::subError()
{
cout << "ERROR: Subscript out of range.\n";
exit(EXIT_FAILURE);
}
//*******************************************************
// getElementAt function. The argument is a subscript. *
// This function returns the value stored at the sub- *
// cript in the array. *
//*******************************************************
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];
}
template <class T>
void SimpleVector<T>::push_front(T val){
// Allocate memory for the array.
try {
T *new_Aptr = new T[arraySize + 1];
for (int i = 0; i < arraySize; i++) {
new_Aptr[i + 1] = aptr[i];
}
arraySize++;
delete[] aptr;
aptr = new_Aptr;
aptr[0] = val;
}
catch(bad_alloc) {
memError();
}
}
template <class T>
void SimpleVector<T>::push_back(T val){
try {
T *new_Aptr = new T[arraySize + 1];
for (int i = 0; i < arraySize; i++) {
new_Aptr[i] = aptr[i];
}
delete[] aptr;
aptr = new_Aptr;
aptr[arraySize] = val;
arraySize++;
}
catch(bad_alloc) {
memError();
}
}
template <class T>
T SimpleVector<T>::pop_front(){
T dummy;
try {
T *new_Aptr = new T[arraySize - 1];
arraySize--;
for (int i = 0; i < arraySize; i++) {
new_Aptr[i] = aptr[i + 1];
}
delete[] aptr;
aptr = new_Aptr;
return dummy;
}
catch(bad_alloc) {
memError();
}
}
template <class T>
T SimpleVector<T>::pop_back(){
T dummy;
try {
T *new_Aptr = new T[arraySize - 1];
arraySize--;
for (int i = 0; i < arraySize; i++) {
new_Aptr[i] = aptr[i];
}
delete[] aptr;
aptr = new_Aptr;
return dummy;
}
catch(bad_alloc) {
memError();
}
}
#endif
And here's the main class provided by my instructor.
main.cpp:
#include "SimpleVector.h"
void fillVec(SimpleVector<int> &);
void addVec(SimpleVector<int> &);
void delVec(SimpleVector<int> &);
void prntVec(SimpleVector<int> &,int);
//Execution Begins Here!
int main(int argc, char** argv) {
//Declare Variables
int size;
//Read in the size
cout<<"What size vector to test?"<<endl;
cin>>size;
SimpleVector<int> sv(size);
//Initialize or input i.e. set variable values
fillVec(sv);
//Display the outputs
prntVec(sv,10);
//Add and subtract from the vector
addVec(sv);
//Display the outputs
prntVec(sv,10);
//Add and subtract from the vector
delVec(sv);
//Display the outputs
prntVec(sv,10);
//Exit stage right or left!
return 0;
}
void addVec(SimpleVector<int> &sv){
int add=sv.size()*0.1;
for(int i=1;i<=add;i++){
sv.push_front(i+add-1);
sv.push_back(i-add);
}
}
void delVec(SimpleVector<int> &sv){
int del=sv.size()*0.2;
for(int i=1;i<=del;i++){
sv.pop_front();
sv.pop_back();
}
}
void fillVec(SimpleVector<int> &sv){
for(int i=0;i<sv.size();i++){
sv[i]=i%10;
}
}
void prntVec(SimpleVector<int> &sv,int n){
cout<<endl;
for(int i=0;i<sv.size();i++){
cout<<sv[i]<<" ";
if(i%n==(n-1))cout<<endl;
}
cout<<endl;
}
I have some leeway with main.cpp(as it is kind of sketchy). More importantly, I need to know where to start with the instructions given. Thank you!!
