Inputting the amount you want displayed in the array - c++

Question

I am writing a program that displays integer arrays. I set the size of the array, but I am wondering how I can ask the user the index of the array that they want listed. Say the const SIZE = 10, and the user wants to see the first three in the array. I want to also write an exception that catches the error if the user input is over the size of the array. If you need to see some code, let me know. Any help is appreciated!
intergerarray.h
class IntArray
{
private:
int *aptr; // Pointer to the array
int arraySize; // Holds the array size
void subscriptError(); // Handles invalid subscripts
public:
class OutOfBoundException
{
public:
int index;
OutOfBoundException(){};
int getInde() { return index; }
};
IntArray(int); // Constructor
IntArray(const IntArray &); // Copy constructor
~IntArray(); // Destructor
int size() const // Returns the array size
{
return arraySize;
}
int &operator[](const int &); // Overloaded [] operator
};
IntergerArray.cpp
IntArray::IntArray(int s)
{
arraySize = s;
aptr = new int[s];
for (int count = 0; count < arraySize; count++)
*(aptr + count) = 0;
}
IntArray::IntArray(const IntArray &obj)
{
arraySize = obj.arraySize;
aptr = new int[arraySize];
for (int count = 0; count < arraySize; count++)
*(aptr + count) = *(obj.aptr + count);
}
IntArray::~IntArray()
{
if (arraySize > 0)
delete[] aptr;
}
void IntArray::subscriptError()
{
cout << "ERROR: Subscript out of range.\n";
exit(0);
}
int &IntArray::operator[](const int &sub)
{
if (sub < 0 || sub >= arraySize)
subscriptError();
return aptr[sub];
}
driver file.cpp
int main()
{
int SIZE = 10;
//int index;
//cout << "enter an index";
//cin >> index;
IntArray table(SIZE);
for (int x = 0; x < SIZE; x++)
table[x] = x;
for (int x = 0; x < SIZE; x++)
cout << table[x] << " ";
cout << endl;
//table[SIZE + 1] = 0;
return 0;
}

Answer 1

Isn't this what you are trying to do? why so much code for such a simple problem?
const int arraySize = 10;
int array[arraySize];
int elementToDis;
do
{
std::cout << "Number of array elements to display: ";
std::cin >> elementToDis;
} while (elementToDis > arraySize || elementToDis < 0); // this is your exeption
for (int ccc(0); ccc < elementToDis; ++ccc)
std::cout << "Index " << ccc << ": " << array[ccc] << '\n';

Answer 2

I think you want to display all elements lower than an index value entered by the user :
Let array[] be the array name of size=10,you can get an index value (say l) from the user and use that value inside a for loop for printing all elements in index lower than l
int array[size]
void disp_in(int l)
{
if(l>=size) // if l greater than or equal to size (as index start at 0)
throw l;
else
{
cout<<"Elements : ";
for(int i=0;i<=l;i++) //if we have say l=2 ,array values in indexes 0,1and 2 will be displayed
cout<<array[i];
}
}
int main ()
{
int l;
cout<<"Enter index : ";
cin>>l; //till this index value, the array value will be displayed
try
{
disp_in(l);
}
catch(int e)
{
cout<<"Index value greater than max index";
}
return 0;
}

Answer 3

You could try something like this:
#include <vector>
#include <iostream>
#include <algorithm>
#include <iterator>
void print_numbers( const std::vector<int>& array, int nNumbers, const char* pszSeparator )
{
if ( nNumbers > static_cast<int>(array.size()) )
{
throw std::exception();
}
std::copy( array.begin(), array.begin() + nNumbers, std::ostream_iterator<int>( std::cout, pszSeparator ) );
}
int main()
{
std::vector<int> array( 10 );
//Just for testing
{
int n = 0;
auto generator = [n]() mutable
{
return n++;
};
std::generate_n( array.begin(), array.size(), generator );
}
try
{
print_numbers(array, 11, "\n");
}
catch ( std::exception e )
{
std::cout << "Error message..." << std::endl;
}
return 0;
}