IntList Example

Source files (for downloading):

• IntList.h
• IntList.cpp
• testIntList.cpp
• Makefile

IntList.h

#ifndef INTLIST_H
#define INTLIST_H
 
class IntList {
 
  public:
    // Constructors
    IntList();
    IntList(int size);
 
    IntList(const IntList &L);              // copy constructor
    ~IntList();                             // destructor
    IntList & operator=(const IntList &L);  // assignment
 
    // Other public member functions
    void addToEnd(int k);   // adds value k to the end of the list
    void print() const;     // prints out the list (using cout)
 
  private:
    static const int SIZE = 10;  // default initial size of array
    int *items;                  // dynamically allocated array of ints
    int numItems;                // number of items currently in the list
    int arraySize;               // current size of the array
};
 
#endif

IntList.cpp

#include <iostream>
#include "IntList.h"
 
using namespace std;
 
// Default (no-argument) constructor
IntList::IntList() : 
items(new int[SIZE]), numItems(0), arraySize(SIZE) {
}
 
 
// Constructor - takes an initial size
IntList::IntList(int size) : 
items(new int[size]), numItems(0), arraySize(size) {
}
 
 
// Copy constructor
IntList::IntList(const IntList &L) : 
items(new int[L.arraySize]), numItems(L.numItems), arraySize(L.arraySize) {
    for (int k = 0; k < numItems; k++)
        items[k] = L.items[k];
}
 
 
// Destructor
IntList::~IntList() {
    delete [] items;
}
 
 
// Overload the assignment operator
IntList & IntList::operator=(const IntList &L) {
    // check for self-assignment - if so, do nothing
    if (this == &L)
        return *this;
 
    else {
        delete [] items;               // free storage pointed to by items
        items = new int[L.arraySize];  // allocate new array
        arraySize = L.arraySize;       // set arraySize
 
        // copy items from L's array to the new array
        // (and also set numItems)
        for (numItems = 0; numItems < L.numItems; numItems++)
            items[numItems] = L.items[numItems];
    }
 
    return *this;
}
 
 
// addToEnd - adds item k to the end of the list
// If the array is full, the array is first doubled in size.
void IntList::addToEnd(int k) {
 
    // check if enough room, if not, double the array
    if (numItems == arraySize) {
        int *newItems = new int[arraySize*2];
        for (int i = 0; i < numItems; i++)
            newItems[i] = items[i];
        delete [] items;
        items = newItems;
        arraySize *= 2;
    }
 
    // add the item
    items[numItems] = k;
    numItems++;
}
 
 
// print - prints out the list to the console (using cout)
void IntList::print() const {
    for (int i = 0; i < numItems; i++)
        cout << items[i] << " ";
    cout << endl;
}

testIntList.cpp

#include <iostream>
#include "IntList.h"
 
using namespace std;
 
void copyAgain(IntList L) {
    IntList Lnew = L;
    Lnew.print();
    L.print();
}
 
int main() {
    IntList L1;
    IntList L2(25);
    
    IntList *p, *q;
    p = new IntList;
    q = new IntList(25);
    
    for (int i = 0; i < 20; i++)
        L1.addToEnd(i+1);
    L1.print();
    
    L2 = L1;
    L2.addToEnd(-1);
    
    IntList L3(L1);
    
    L1.print();
    L2.print();
    L3.print();
    
    copyAgain(L3);
    
//    delete p;
//    delete q;
 
    return 0;
}

Makefile

# Makefile for the IntList example
# (all this goes in a file named 'Makefile')
  
main: testIntList.o IntList.o
	g++ testIntList.o IntList.o
 
testIntList.o: testIntList.cpp IntList.h
	g++ -c testIntList.cpp
 
IntList.o: IntList.cpp IntList.h
	g++ -c IntList.cpp
 
clean:
	rm *.o

Using the Makefile

king06(1)% ls
IntList.cpp  IntList.h	Makefile  testIntList.cpp 
  
king06(2)% make
g++ -c testIntList.cpp
g++ -c IntList.cpp
g++ testIntList.o IntList.o
 
king06(3)% ls
a.out	     IntList.h	Makefile	 testIntList.o
IntList.cpp  IntList.o	testIntList.cpp  
 
king06(4)% rm IntList.o
rm: remove regular file `IntList.o'? y
 
king06(5)% make
g++ -c IntList.cpp
g++ testIntList.o IntList.o
 
king06(6)% make clean
rm *.o
 
king06(7)% ls
a.out  IntList.cpp  IntList.h  Makefile  testIntList.cpp  
 
king06(8)% make
g++ -c testIntList.cpp
g++ -c IntList.cpp
g++ testIntList.o IntList.o
 
king06(9)% make IntList.o
make: `IntList.o' is up to date.