C++程序記錄三

//median.hpp
//median函數模板在保存未知類型對象的vector中查找中間值
#ifndef MEDIAN_H_
#define MEDIAN_H_
#include<vector>
#include<algorithm>
using std::vector;
//如果vector中有中間值，則返回true，並將中間值記錄在第二個參數中
//否則，返回false
template <typename T>
bool median(const vector< T>& , T& );
#include "median.hpp"//引入函數模板的實現文件
#endif // MEDIAN_H_

//median.cpp
//定義median函數模板的實現文件(源文件)
#include<iostream>
#include<vector>
using std::vector;
template <typename T>
bool median(const vector<T>&  c, T& m)
{
    //構造temp爲c的副本
    vector<T> temp(c);
    //如果容器中包含偶數個元素，則沒有中間值，返回false
    if(temp.size() % 2 == 0)
        return false;
    //將元素排序
    sort(temp.begin(),temp.end());
    //判斷中間點元素是否爲中間值，是則返回true，並用m記錄中間值
    //否則返回false
    typename vector<T>::size_type  index = temp.size() / 2;
    if(temp[index] > temp[index-1]
       && temp[index] < temp[index+1])
       {
           m = temp[index];
           return true;
       }
       else
       {
           return false;
       }
}

#include <iostream>
#include<vector>
#include "median.hpp"
#include "median.cpp"
using namespace std;
int main()
{
    int ia1[] = {1,2,3,4,5,6,7};
    int ia2[] = {1,2,3,4};
    int ia3[] = {1,2,2,3,4,5,6};
    vector<int> ivec1(ia1,ia1+7);
    vector<int> ivec2(ia2,ia2+4);
    vector<int> ivec3(ia3,ia3+7);
    int m;
    if(median(ivec1, m))
        cout << "median: "<< m << endl;
    else
        cout << "no median: " << endl;
    if(median(ivec2, m))
        cout << "median: " << m << endl;
    else
        cout << "no median: " << endl;
    if(median(ivec3, m))
        cout << "median: " << m << endl;
    else
        cout << "median: " << endl;
    return 0;
}

template <class elemType> class ListItem;
template <class elemType> class List
{
public:
    List<elemType>();
    List<elemType>(const List<elemType> &);
    List<elemType>& operator=(const List<elemType> &);
    ~List();
    void insert(ListItem<elemType> *ptr, elemType value);
    ListItem<elemType> *find(elemType value);
private:
    ListItem<elemType> *front;
    ListItem<elemType> *end;
}
template <class Type>
Queue<Type>&  Queue<Type>::operator = (const Queue &orig)
{
    destroy();
    copy_elem(orig);
      
    return *this;
}
   
template <class Type>
Queue<Type>& Queue<Type>::operator = (const Queue &orig)
{
    QueueItem<Type> *p = orig.head, *q;
    while(p != 0)
    {
        q = new QueueItem<Type>(p -> item);
        if(p == orig.head)
            head = tail = q;
        tail -> next = q;
        tail = q;
        p = p->next;
    }
}