一个数组类【模板类】

 1 //MyList.h
 2 #ifndef MyList_h
 3 #define MyList_h
 4 
 5 #include <iostream>
 6 using namespace std;
 7 
 8 class rangeerror{}; //the error class used to catch error
 9 template <class T> class MyList;
10 // the following are friend functoins statements
11 template <class T> void Qsort(T a[],int, int, bool);
12 template <class T> ostream & operator<<(ostream &os,const MyList<T> &obj);
13 template <class T> MyList<T> operator+ (const MyList<T> &l1, const MyList<T> &l2);
14 template <class T> MyList<T> operator+ (const MyList<T> &l1, const T &item);
15 template<class T>
16 class MyList{
17     friend void Qsort<>(T a[],int low,int high,bool less);
18     friend ostream &operator<< <>(ostream &os, const MyList<T> &obj);
19     friend MyList<T> operator+ <>(const MyList<T> &l1, const MyList<T> &l2);
20     friend MyList<T> operator+ <>(const MyList<T> &l1, const T &item);  
21 private:
22     T *a;
23     int size;
24     int capa;   //record the space available
25     void double_space(); // double the remained space if not enough
26 public:    
27     
28     MyList(int s = 0):size(s),capa(s){ //constructor
29         if (capa == 0) capa = 100;
30         a = new T[capa];
31     }
32     MyList(int num, const T &item){  //constructe a object with num items
33         size = capa = num;
34         a = new T[capa];
35         for (int i = 0;i < num;++i) a[i] = item;
36     }
37     MyList(const MyList &l){   // copy constructor
38         size = capa = l.size;
39         a = new T[capa];
40         for (int i = 0;i < size;++i) a[i] = l.a[i];
41     }
42     MyList(T* arr, int len){//constructe by the previous len items of arr
43         size = capa = len;
44         a = new T[capa];
45         for (int i = 0;i < len;++i) a[i] = arr[i];
46     }
47     void push(const T &item);//add item to the last of MyList
48     T pop();                //delete the last item and return it
49     void insert(int index, const T &item);//insert item in the position of index
50     void clean(){erase(0,size-1);}//clear the list
51     int get_size() {return size;}//return the number of MyList
52     void erase(int start, int end); //delete items between start(included) and end(included)
53     T get_item(int index);//return index-th item
54     MyList get_item(int start, int end);//return a sublist from start to end(negative indexes are allowed
55     int count(const T &item);//return the number of items in MyList which equal to item
56     void remove(const T &item);//delete the first element in MyList which equals to item
57     T &operator[](int index); // index operator which return the reference of the element
58     MyList &operator = (const MyList &l);// assignment
59     MyList &operator += (const T &item);//equal to push(T item)
60     MyList &operator += (const MyList &l);//add a new MyList in the end of list
61     void sort(bool less=true);//quick sort the list(if less is true, the order is by increasing, other wise decreasing
62     void reverse();//reverse the elements in MyList
63     ~MyList(){delete [] a;} //destrctor
64 };
65 
66 #endif

  1 // Mylist.cpp : the realization of class MyList
  2 
  3 #include "stdafx.h"
  4 #include "Mylist.h"
  5 
  6 template <class T>
  7 MyList<T> operator+(const MyList<T> &l1,const MyList<T> &l2){
  8     int len = l1.size + l2.size;
  9     MyList<T> l3(len);
 10     for (int i = 0;i < l1.size;++i) l3.a[i] = l1.a[i];
 11     for (int i = l1.size;i < len;++i) l3.a[i] = l2.a[i-l1.size];
 12     return l3;
 13 }
 14 template <class T>
 15 ostream & operator<< (ostream &os,const MyList<T> &l){
 16     for (int i = 0;i < l.size;++i) os<<l.a[i]<<‘ ‘;
 17     os<<endl;
 18     return os;
 19 }
 20 template <class T> 
 21 MyList<T> operator+(const MyList<T> &l,const T &item){
 22     MyList<T> l2(l.size+1);
 23     for (int i = 0;i < l.size;++i) l2.a[i] = l.a[i];
 24        l2.a[l2.size-1] = item;
 25        return l2;
 26 }
 27 template <class T>
 28 void MyList<T>::double_space(){//数组大小不够的时候将数组大小翻倍的操作。
 29     capa *= 2;
 30     T *newa = new T[capa];
 31     for (int i = 0;i < size;++i) newa[i] = a[i];
 32     delete [] a;
 33     a = newa;
 34 }
 35 
 36 template <class T>
 37 void MyList<T>::push(const T &item){
 38     if (size == capa) double_space();
 39     a[size++] = item;
 40 }
 41 template <class T>
 42 T MyList<T>::pop(){
 43     try {
 44         if (size==0) throw rangeerror();
 45         T tem = a[size-1];
 46         size--;
 47         return tem;
 48     }
 49     catch(rangeerror) {
 50         cout<<"out of range!";
 51         exit(0);
 52     }
 53 }
 54 template <class T>
 55 void MyList<T>::insert(int index,const T &item){
 56     try {
 57         if (index<0 || index>=size) throw rangeerror();
 58         if (size == capa) double_space();
 59         for (int i = size;i > index;--i) a[i] = a[i-1];
 60         a[index] = item;
 61         size++;
 62     }
 63     catch(rangeerror){
 64         cout<<"out of range!";
 65         exit(0);
 66     }
 67 }
 68 template <class T>
 69 void MyList<T>::erase(int start,int end){
 70     try {
 71         if (start<0 || end>size-1 || end<start) throw rangeerror();
 72         for (int i = end+1;i < size;++i) a[start+i-end-1] = a[i];
 73         size -= end-start+1;
 74     }
 75     catch (rangeerror){
 76         cout<<"out of range!";
 77         exit(0);
 78     }
 79 }
 80 template <class T>
 81 T MyList<T>::get_item(int index){
 82     try{
 83         if (index<0 || index>size-1) throw rangeerror();
 84         return a[index];
 85     }
 86     catch(rangeerror) {
 87         cout<<"out of range!";
 88         exit(0);
 89     }
 90 }
 91 template <class T>
 92 MyList<T> MyList<T>::get_item(int start,int end){
 93     try{
 94         if (start<0) start += size;
 95         if (end<0) end += size;
 96         if (start>=size || start<0 ||end>=size||end<0) throw rangeerror();
 97         int len = end - start + 1;
 98         if (len>0){
 99             MyList<T> t(len);
100             for (int i = 0;i < len;++i) t.a[i] = a[start+i];
101             return t;
102         }else{
103             MyList<T> t;
104             return t;
105         }        
106     }
107     catch(rangeerror){
108         cout<<"out of range!";
109         exit(0);
110     }
111 }
112 template <class T>
113 int MyList<T>::count(const T &item){
114     int num = 0;
115     for (int i =0;i < size;++i) if (a[i] == item) num++;
116     return num;
117 }
118 template <class T>
119 void MyList<T>::remove(const T &item){
120     for (int i = 0;i < size;++i) if (a[i] == item){
121         erase(i,i);
122         break;
123     }
124 }
125 template <class T>
126 void MyList<T>::reverse(){
127     if (size<2) return;
128     for (int i = 0;i < size/2;++i) {
129         T tem = a[i];
130         a[i] = a[size - i - 1];
131         a[size-i-1] = tem;
132     }
133 }
134 template <class T>
135 void MyList<T>::sort(bool less){
136     if (size==0) return;
137     Qsort(a,0,size-1,less); 
138 }
139 template <class T>
140 MyList<T>& MyList<T>::operator = (const MyList<T> &l){
141     if (this == &l) return *this;
142     delete [] a;
143     capa = size = l.size;
144     a = new T[size];
145     for (int i = 0;i < size;++i) a[i] = l.a[i];
146     return *this;
147 }
148 template <class T>
149 MyList<T>& MyList<T>::operator +=(const T &item){
150     push(item);
151     return *this;
152 }
153 template <class T>
154 MyList<T>& MyList<T>::operator +=(const MyList<T> &l){
155     *this = *this + l;
156     return *this;
157 }
158 template <class T>
159 T &MyList<T>::operator[](int index){
160        try {
161            if (index < 0 || index >= size) throw rangeerror();
162         return a[index];
163     }
164        catch(rangeerror){
165         cout<<"out of range!";
166         exit(0);
167     }
168 } 
169 template <class T>
170 void Qsort(T a[],int low,int high,bool less){
171     if (high<=low) return;
172     T tem = a[low];
173     int l = low,r = high;
174     if (less) {
175         do {
176             while (l<r && a[r]>=tem) r--;
177             if (l<r) a[l++] = a[r];
178             while (l<r && a[l]<=tem) l++;
179             if (l<r) a[r--] = a[l];
180             a[l] = tem;
181         }while(l!=r);
182         
183     }else{
184         do {
185             while (l<r && a[r]<=tem) r--;
186             if (l<r) a[l++] = a[r];
187             while (l<r && a[l]>=tem) l++;
188             if (l<r) a[r--] = a[l];
189             a[l] = tem;
190         }while (l!=r);        
191     }
192     Qsort(a,low,l-1,less);
193     Qsort(a,l+1,high,less);
194 }
195 
196 // the following is the test code
197 int _tmain(int argc, _TCHAR* argv[])
198 {
199     MyList<int> a, b;
200     int i;
201     for (i=0; i<5; ++i)
202         a.push(i);// a = [0, 1, 2, 3, 4]
203     a[3] = 15; // a = [0, 1, 2, 15, 4]
204     a.sort();// a = [0, 1, 2, 4, 15]
205     a.reverse();// a = [15, 4, 2, 1, 0]
206     a += 12;// a = [15, 4, 2, 1, 0, 12]
207     for (i=0; i<a.get_size(); ++i)
208         cout<<a[i]<<endl;
209     b = a.get_item(4, -3); // b = [] *若start > end，返回空数组
210     b = a.get_item(3, -1);cout<<b<<endl;// b = [1, 0, 12] 
211     a += b;// a = [15, 4, 2, 1, 0, 12, 1, 0, 12]
212     for (i=0; i<a.get_size(); ++i)
213         cout<<a.get_item(i)<<endl;
214     cout<<a.count(5)<<endl;
215     b.clean();// b = []
216     cout<<b.get_size()<<endl;
217     a.erase(2, 5);// a = [15, 4, 0, 12]
218     b = a + a;// b = [15, 4, 0, 12, 15, 4, 0, 12]
219     b.insert(3, 116);// b = [15, 4, 0, 116, 12, 15, 4, 0, 12]
220     b.remove(4);// b = [15, 0, 116, ...]
221     cout<<b<<endl;
222     MyList<double> c(10, 3.14);
223     for (i=0; i<100; ++i) c.push(1.1*i);
224     cout<<c.get_item(100, 105)<<endl;
225     return 0;
226 }