Concatenating two string arrays without using STL or vectors in C ++
I'm teaching myself C ++ hence terrible naming and super simple question. I am trying to concatenate two arrays in C ++. The array is of type string. Their constructor allows them to have a standard capacity of 12. So basically I am trying to concatenate the arrays so that I have an array that can hold 24 elements. I don't want to use vectors and I don't want to use STL. There are several items in arrays, but they don't completely fill their possibilities. Below you will find the code.
Here's my ArrayBag.h def class:
#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;
std::vector<ItemType> toVector() const;
}; // end ArrayBag
#endif
And here is my real implementation of the class.
#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
ArrayBag<string> merge(const ArrayBag<string>& oneBag,
const ArrayBag<string>& anotherBag)
{
int sizeOnebag, sizeAnotherbag, newBagsize;
sizeOnebag = oneBag.getCurrentSize();
sizeAnotherbag = anotherBag.getCurrentSize();
newBagsize = sizeAnotherbag + sizeOnebag;
In the example above, I took the size of two packages and created a new int that contains the size of the two original arrays. But from there I'm not sure what to do. I tried below. But get a compiler warning every time.
ArrayBag<string> finalBag;
int itemCount = finalBag.getCurrentSize();
if (itemCount > newBagsize){
newBagsize++;
itemCount = finalBag.getCurrentSize();
finalBag[itemCount];
}
Below is BagInterface.h
#ifndef _BAG_INTERFACE
#define _BAG_INTERFACE
#include <vector>
using namespace std;
template<class ItemType>
class BagInterface
{
public:
/** Gets the current number of entries in this bag.
@return The integer number of entries currently in the bag. */
virtual int getCurrentSize() const = 0;
/** Sees whether this bag is empty.
@return True if the bag is empty, or false if not. */
virtual bool isEmpty() const = 0;
/** Adds a new entry to this bag.
@post If successful, newEntry is stored in the bag and
the count of items in the bag has increased by 1.
@param newEntry The object to be added as a new entry.
@return True if addition was successful, or false if not. */
virtual bool add(const ItemType& newEntry) = 0;
/** Removes one occurrence of a given entry from this bag,
if possible.
@post If successful, anEntry has been removed from the bag
and the count of items in the bag has decreased by 1.
@param anEntry The entry to be removed.
@return True if removal was successful, or false if not. */
// virtual bool remove(const ItemType& anEntry) = 0;
/** Removes all entries from this bag.
@post Bag contains no items, and the count of items is 0. */
virtual void clear() = 0;
// I commented this out because I did not implement it.
/** Counts the number of times a given entry appears in bag.
@param anEntry The entry to be counted.
@return The number of times anEntry appears in the bag. */
virtual int getFrequencyOf(const ItemType& anEntry) const = 0;
// I commented this out because I did not implement it.
/** Tests whether this bag contains a given entry.
@param anEntry The entry to locate.
@return True if bag contains anEntry, or false otherwise. */
virtual bool contains(const ItemType& anEntry) const = 0;
/** Empties and then fills a given vector with all entries that
are in this bag.
@return A vector containing all the entries in the bag. */
virtual vector<ItemType> toVector() const = 0;
virtual bool remove(const ItemType& anEntry) = 0;
}; // end BagInterface
#endif
And here is my main file.
#include <iostream>
#include <string>
#include "ArrayBag.h"
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
+3
source to share
2 answers
You can declare merge
as a friend:
public:
friend ArrayBag<string> merge(ArrayBag<string> a, ArrayBag<string> b);
ArrayBag();
int getCurrentSize() const;
bool isEmpty() const;
...
Then define a merge like:
ArrayBag<string> merge(ArrayList<string> a, ArrayList<string> b) {
int newsz = a.getCurrentSize() + b.getCurrentSize();
if (newsz > a.DEFAULT_CAPACITY)
// do something here
abort();
ArrayBag<string> result;
for (int c=0; c<a.getCurrentSize(); ++c)
result.add(a.items[c]);
for (int c=0; c<b.getCurrentSize(); ++c)
result.add(b.items[c]);
return result;
}
Of course the cleaner way is to add a substring operator:
T operator[](size_t x) const { return items[x]; }
Then you do not have merge
to be a friend and can be replaced a.items[c]
and b.items[c]
only a[c]
and b[c]
.
+2
source to share
You have not ArrayBag
provided your code for , but if you want to concatenate two C-style arrays, you will have to create a new array with 24 elements and manually copy (or move, if using C ++ 11 or C ++ 14) the elements, and then remove old arrays.
By the way, if you are using std :: string, you are already using STL.
0
source to share