Getting errors when switching my array class to a template - c++

Question

I created a class that created an array of ints and stored them as a vector would. I had it all working, but then I had to turn it into a template so that I could store more than just ints. I am getting the following errors and am not sure how to address them:
subscript is not of integral type (myvector.h line 70)
which is the line that says (vectorArray[vectorSize] = n;)
'initializing': conversion from 'double' to 'unsigned int', possible loss of data (myvector.h line 88)
Which is the line that says (T *tempArray = new T[newCapacity];)
subscript is not of integral type porj08 (myvector.h line 98)
Which is the line that says (tempArray[i] = vectorArray[i];)
'initializing': conversion from 'double' to 'unsigned int', possible loss of data (myvector.h line 102)
Which is the line that says (vectorArray = new T[newCapacity];)
subscript is not of integral type porj08 (myvector.h line 113)
Which is the line that says (vectorArray[vectorSize] = n;)
It obviously has something to do with vectorArray but I can not figure out for the life of me what I did wrong.
MyVector.h
#pragma once
#include <iostream>
#include "stdafx.h"
using namespace std;
template <class T>
class MyVector
{
private:
T vectorSize;
T vectorCapacity;
T *vectorArray;
public:
MyVector() {
vectorArray = new T[10];
}
T size();
T capacity();
void clear();
void push_back(T n);
T at(T n);
friend ostream& operator<<(ostream& os, MyVector vt);
MyVector operator=(MyVector&);
};
/*
* TEMPLATE FUNCTIONS
*/
//Return array size
template<class T>
T MyVector<T>::size()
{
return vectorSize;
}
// Return array capacity
template<class T>
T MyVector<T>::capacity()
{
return vectorCapacity;
}
// clear array values
template<class T>
void MyVector<T>::clear()
{
for (int i = 0; i < sizeof(vectorArray); i++)
{
vectorArray[i] = '\0';
}
vectorSize = 0;
vectorCapacity = 2;
}
// Add number to array and double array size if needed
template<class T>
void MyVector<T>::push_back(T n)
{
int test = 100;
if (vectorCapacity > vectorSize)
{
vectorArray[vectorSize] = n;
vectorSize++;
}
else {
if (vectorCapacity == 0) {
vectorArray = new T[4];
vectorArray[0] = n;
vectorCapacity = 4;
vectorSize++;
}
else {
T newCapacity = vectorCapacity * 2;
// Dynamically allocate a new array of integers what is somewhat larger than the existing array.An algorithm that is often used is to double the size of the array.
T *tempArray = new T[newCapacity];
// Change capacity to be the capacity of the new array.
vectorCapacity = newCapacity;
// Copy all of the numbers from the first array into the second, in sequence.
for (T i = 0; i < MyVector::size(); i++)
{
tempArray[i] = vectorArray[i];
}
delete[] vectorArray;
vectorArray = new T[newCapacity];
for (int i = 0; i < MyVector::size(); i++)
{
vectorArray[i] = tempArray[i];
}
delete[] tempArray;
// Add the new element at the next open slot in the new array.
vectorArray[vectorSize] = n;
// Increment the size;
vectorSize++;
}
}
}
// Return Value and given point in array
template<class T>
T MyVector<T>::at(T n)
{
return vectorArray[n];
}
Main.cpp
#include "stdafx.h"
#include <string>
#include "MyVector.h"
const double FRACTION = 0.5;
int main()
{
cout << "\nCreating a vector of doubles named Sam\n";
MyVector<double> sam;
cout << "\nPush 12 values into the vector.";
for (int i = 0; i < 12; i++)
sam.push_back(i + FRACTION);
cout << "\nHere is sam: ";
cout << sam;
cout << "\n---------------\n";
cout << "\nCreating an empty vector named joe";
MyVector<double> joe;
// test assignment
joe = sam;
cout << "\nHere is joe after doing an assignment:\n ";
cout << joe;
cout << "\n---------------\n";
// test the copy constructor
MyVector<double> bill = sam;
cout << "\nHere is bill after creating it using the copy constructor:\n ";
cout << bill;
cout << "\n---------------\n";
cout << endl;
system("PAUSE");
return 0;
}

Answer 1

T vectorSize;
T vectorCapacity;
If T is float for example, these will be float, obviously. You don't want that. Type of these members should not be dependent on the type T of elements, make it std::size_t, for example:
std::size_t vectorSize;
std::size_t vectorCapacity;
Then, beware sizeof(pointer) (you used one in clear), use vectorSize or vectorCapacity for loop conditions instead. That should cover all.