I don't know C++ very well and I'm teaching myself about ADT's and data structures. Unfortunately every time I need to compile the code I get the classic xcode error: mach link error. I tend to understand these errors when they're in objective-c (because it usually means that I'm missing a file). I made sure to add the file to my target to avoid this issue, but that didn't seem to work. Neither did the classic turn Xcode on and off trick.
Below is the error and code:
Undefined symbols for architecture x86_64:
"ArrayBag<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >::getIndexOf(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) const", referenced from:
ArrayBag<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >::remove(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) in main.o
"ArrayBag<int>::getIndexOf(int const&) const", referenced from:
ArrayBag<int>::remove(int const&) in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
#ifndef _ARRAY_BAG
#define _ARRAY_BAG
#include "BagInterface.h"
#include <vector>
template<class ItemType>
class ArrayBag : public BagInterface<ItemType>
{
private:
static const int DEFAULT_CAPACITY = 24; // the bag size a bit bigger to allow
// adding bags.
ItemType items[DEFAULT_CAPACITY]; // Array of bag items
int itemCount; // Current count of bag items
int maxItems; // Max capacity of the bag
// Returns either the index of the element in the array items that
// contains the given target or -1, if the array does not contain
// the target.
int getIndexOf(const ItemType& target) const;
public:
ArrayBag();
int getCurrentSize() const;
bool isEmpty() const;
bool add(const ItemType& newEntry);
void clear();
bool remove(const ItemType& anEntry);
bool contains(const ItemType& target) const;
int getFrequencyOf(const ItemType& anEntry) const;
ArrayBag<string> merge(ArrayBag<string> a, ArrayBag<string> b);
std::vector<ItemType> toVector() const;
#include "ArrayBag.h"
#include <cstddef>
template<class ItemType>
ArrayBag<ItemType>::ArrayBag(): itemCount(0), maxItems(DEFAULT_CAPACITY)
{
} // end default constructor
template<class ItemType>
int ArrayBag<ItemType>::getCurrentSize() const
{
return itemCount;
} // end getCurrentSize
template<class ItemType>
bool ArrayBag<ItemType>::isEmpty() const
{
return itemCount == 0;
} // end isEmpty
template<class ItemType>
bool ArrayBag<ItemType>::add(const ItemType& newEntry)
{
bool hasRoomToAdd = (itemCount < maxItems);
if (hasRoomToAdd)
{
items[itemCount] = newEntry;
itemCount++;
} // end if
return hasRoomToAdd;
} // end add
template<class ItemType>
void ArrayBag<ItemType>::clear()
{
itemCount = 0;
} // end clear
template<class ItemType>
bool ArrayBag<ItemType>::remove(const ItemType& anEntry)
{
int locatedIndex = getIndexOf(anEntry);
bool canRemoveItem = !isEmpty() && (locatedIndex > -1);
if (canRemoveItem)
{
itemCount--;
items[locatedIndex]=items[itemCount];
}//end if
return canRemoveItem;
} //end remove
template<class ItemType>
bool ArrayBag<ItemType>::contains(const ItemType& anEntry) const
{
bool found = false;
int curIndex = 0; //current array index
while(!found && (curIndex < itemCount))
{
if(anEntry == items[curIndex])
{
found = true;
} //end if
curIndex++; //increment to the next entry
} //end while
return found;
}
template<class ItemType>
int ArrayBag<ItemType>::getFrequencyOf(const ItemType& anEntry) const
{
int frequency = 0;
int curIndex = 0; //current index array
while(curIndex < itemCount)
{
if (items[curIndex] == anEntry)
{
frequency++;
} //end if
curIndex++; //incremenet to next entry
} //end while
return frequency;
} //end getFrequencyOf
template<class ItemType>
vector<ItemType> ArrayBag<ItemType>::toVector() const
{
vector<ItemType> bagContents;
for (int i = 0; i < itemCount; i++)
bagContents.push_back(items[i]);
return bagContents;
} // end toVector
#include <iostream>
#include <string>
#include "ArrayBag.h"
#include "ArrayBag.cpp"
using namespace std;
void displayBag(ArrayBag<string>& bag)
{
cout << "The bag contains " << bag.getCurrentSize()
<< " items:" << endl;
vector<string> bagItems = bag.toVector();
int numberOfEntries = (int)bagItems.size();
for (int i = 0; i < numberOfEntries; i++)
{
cout << bagItems[i] << " ";
} // end for
cout << endl << endl;
} // end displayBag
void displayBag(ArrayBag<int>& bag)
{
cout << "The bag contains " << bag.getCurrentSize()
<< " items:" << endl;
vector<int> bagItems = bag.toVector();
int numberOfEntries = (int)bagItems.size();
for (int i = 0; i < numberOfEntries; i++)
{
cout << bagItems[i] << " ";
} // end for
cout << endl << endl;
} // end displayBag
int sumOfBag(ArrayBag<int>& aBag)
{
int sum=0;
vector<int> aBagvector = aBag.toVector();
int numberOfEntries = (int) aBagvector.size();
for (int i = 0; i < numberOfEntries; i++)
{
sum += aBagvector[i];
}
//cout << "The sum of the bag is " << sum << endl;
return sum;
}
void bagTester(ArrayBag<string>& bag)
{
cout << "isEmpty: returns " << bag.isEmpty()
<< "; should be 1 (true)" << endl;
displayBag(bag);
string items[] = {"one", "two", "three", "four", "five", "one"};
cout << "Add 6 items to the bag: " << endl;
for (int i = 0; i < 6; i++)
{
bag.add(items[i]);
} // end for
displayBag(bag);
cout << "isEmpty: returns " << bag.isEmpty()
<< "; should be 0 (false)" << endl;
cout << "getCurrentSize: returns " << bag.getCurrentSize()
<< "; should be 6" << endl;
cout << "Try to add another entry: add(\"extra\") returns "
<< bag.add("extra") << endl;
displayBag(bag);
} // end bagTester
int main()
{
ArrayBag<string> bag;
cout << "Testing the Array-Based Bag:" << endl;
cout << "The initial bag is empty." << endl;
bagTester(bag);
ArrayBag<string> bag_of_strings1;
string items[] = {"tom","dick","harry"};
for (int i=0; i<3; i++) {bag_of_strings1.add(items[i]);}
displayBag(bag_of_strings1);
ArrayBag<string> bag_of_strings2;
string new_items[] = {"now","is","the","time","for","all"};
for(int i=0; i<6; i++){
bag_of_strings2.add(new_items[i]);
}
displayBag(bag_of_strings2);
//ArrayBag<string> newbag=merge(bag_of_strings1,bag_of_strings2);
//displayBag(newbag);
ArrayBag<int> bag_of_ints;
int array_of_ints[]={6,7,85,9,12,15};
for (int i=0;i<6;i++){
bag_of_ints.add(array_of_ints[i]);
}
displayBag(bag_of_ints);
cout<<sumOfBag(bag_of_ints)<<endl;
return 0;
} // end main
The linker is telling you there is no implementation for ArrayBag::getIndexOf. The implementation is also missing from your code dump. Try adding this:
int ArrayBag<ItemType>::getIndexOf(const ItemType& target) const
{
// TODO
return 0;
}
Unlike normal classes, template classes should be defined in a single header file without a corresponding .cpp file.