本文共 5140 字，大约阅读时间需要 17 分钟。

程序示例

stcktp1.h

#ifndef STCKTP1_H_#define STCKTP1_H_template 
   
    class Stack{  private:    enum {SIZE = 10};    int stacksize;    Type * items;    int top;  public:    explicit Stack(int ss = SIZE);    Stack(const Stack & st);    ~Stack() {delete [] items;}    bool isempty() {return top == 0;}    bool isfull() {return top == stacksize;}    bool push(const Type & item);    bool pop(Type & item);    Stack & operator= (const Stack & st);};template 
    
     Stack
     
      ::Stack(int ss) : stacksize(ss), top(0){  items = new Type [stacksize];}template 
      
       Stack
       
        ::Stack (const Stack & st){  stacksize = st.stacksize;  top = st.top;  items = new Type [stacksize];  for (int i = 0; i < top; i++)    items[i] = st.items[i];}template
        
         bool Stack
         
          ::push(const Type & item){ if (top < stacksize) { items[top++] = item; return true; } else return false;}template
          
           bool Stack
           
            ::pop(Type & item){ if (top > 0) { item = items[--top]; return true; } else return false;}template
            
             Stack
             
               & Stack
              
               ::operator=(const Stack
               
                 & st){ if (this == &st) return *this; delete [] items; stacksize = st.stacksize; top = st.top; items = new Type [stacksize]; for(int i = 0; i < top; i++) items[i] = st.items[i]; return *this;}#endif
               
              
             
            
           
          
         
        
       
      
     
    
   

stkoptr1.cpp

#include 
   
    #include 
    
     #include 
     
      #include "stcktp1.h"const int Num = 10;int main(){  std::srand(std::time(0));  std::cout << "Please enter stack size: ";  int stacksize;  std::cin >> stacksize;  Stack
      
        st(stacksize);  const char* in[Num] = {    "1: Hank Gilgamesh", "2: Kiki Ishtar",    "3: Betty Rocker", "4: Ian Flagranti",    "7: Joy Almondo", "8: Xaverie Paprika",    "9: Juan Morre", "10: Misha Mache"  };  const char* out[Num];  int processed = 0;  int nextin = 0;  while (processed < Num)  {    if (st.isempty())      st.push(in[nextin++]);    else if(st.isfull())      st.pop(out[processed++]);    else if (std::rand() % 2 && nextin < Num)      st.push(in[nextin++]);    else      st.pop(out[processed++]);  }  for (int i = 0; i < Num; i++)    std::cout << out[i] << std::endl;  std::cout << "Bye\n";  return 0;}
      
     
    
   

表达式参数类模板：

程序示例：

arraytp.h

#ifndef ARRAYTP_H_#define ARRAYTP_H_#include 
   
    #include 
    
     template
     
      class ArrayTP{  private:    T ar[n];  public:    ArrayTP() {};    explicit ArrayTP(const T & v);    virtual T & operator[] (int i);    virtual T operator[] (int i) const;};template
      
       ArrayTP
       
        ::ArrayTP(const T & v){  for (int i = 0; i < n; i++)    ar[i] = v;}template
        
         T & ArrayTP
         
          ::operator[](int i){ if (i < 0 || i >= n) { std::cerr << "Error in array limits: " << i << " is out of range\n"; std::exit(EXIT_FAILURE); } return ar[i];}template 
          
           T ArrayTP
           
            ::operator[](int i) const{ if (i < 0 || i >= n) { std::cerr << "Error in array limits: " << i << " is out of range\n"; std::exit(EXIT_FAILURE); } return ar[i];}#endif
           
          
         
        
       
      
     
    
   

twod.cpp

#include 
   
    #include "arraytp.h"int main(){  using std::cout;  using std::endl;  ArrayTP
    
      sums;  ArrayTP
     
       aves;  ArrayTP< ArrayTP
      
       , 10> twodee;  int i, j;  for (i = 0; i < 10; i++)  {    sums[i] = 0;    for (j = 0; j < 5; j++)    {      twodee[i][j] = (i + 1) * (j + 1);      sums[i] += twodee[i][j];    }    aves[i] = (double) sums[i] / 10;  }  for (i = 0; i < 10; i++)  {    for (j = 0; j < 5; j++)    {      cout.width(2);      cout << twodee[i][j] << ' ';    }    cout << ": sum = ";    cout.width(3);    cout << sums[i] << ", average = " << aves[i] << endl;  }  cout << "Done.\n";  return 0;}
      
     
    
   

运行结果：

多类型模板参数

就是模板参数是多个class

程序示例pairs.cpp

#include 
   
    #include 
    
       using std::cout;   using std::cin;  using std::endl;  using std::string;template 
     
      class Pair{  private:    T1 a;    T2 b;  public:    T1 & first();    T2 & second();    T1 first() const { return a;}    T2 second() const { return b;}    Pair(const T1 & aval, const T2 & bval) : a(aval), b(bval) {}    Pair() {}};template
      
       T1 & Pair
       
        ::first(){// 这个我是在测试调哪个first()  cout << "1&";  return a;}template
        
         T2 & Pair
         
          ::second(){ cout << "2&"; return b;}int main(){ using std::cout; using std::cin; using std::endl; using std::string; Pair
          
            ratings[4] = { Pair
           
             ("The Purpled Duck", 5), Pair
            
              ("Jaquie's Frisco Al Fresco", 4), Pair
             
               ("Cafe Souffle", 5), Pair
              
                ("Bertie's Eats", 3) }; int joints = sizeof(ratings) / sizeof (Pair
               
                ); cout << "Rating:\t Eatery\n"; for (int i = 0; i < joints; i++) cout << ratings[i].second() << ":\t " << ratings[i].first() << endl; cout << "Oops! Revised rating:\n"; ratings[3].first() = "Bertie's Fab Eats"; ratings[3].second() = 6; cout << ratings[3].second() << ":\t " << ratings[3].first() << endl; return 0;}
               
              
             
            
           
          
         
        
       
      
     
    
   

类模板类型参数和非类型参数都可以指定默认值。 函数模板不支持类型参数带默认值。 但是非类型参数可以

以上都是模板隐式实例化

还有显示实例化

。。嗯。。。这有毛用？

然后是显示具体化

就是为特定具体类另外单独定义模板内容的

template <> class SortedArray<const char *> 例子中是 SortedArray<const char char*> 完全不知道为毛要多一个char

在使用char* 类的时候就会调用该显示具体化的模板

部分具体化

template<class T1> Pair<T1, int> {...} 

吧没有具体化的参数丢到前面的那个<>中去

C++调用模板的顺序：

具体化程度越高越优先调用。 有指针具体化的先调指针具体化版本。不然就用通用的转换。

完结

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