C++ 模板和泛型编程（掌握Vector等容器的使用）

#include <iostream>
using namespace std;
template <class T>  // 模板
 
T min(T a[], int n)
{
    int i;
    T minv = a[0];
    for (i = 1; i < n; i++)  // n-1次 
    {   
        // n为数组长 
        if (minv > a[i])
        {
            minv = a[i];        
        }   
    }
    
    return minv;
}

int main()
{
    int a[] = {8, 10, 0, 1, 7, 4, 9, 6, 11};
    double b[] = {1.2, -3.4, 6.9, 7.2, 8.9};    
       
    cout << "a数组的最小值为:" << min(a, 9) << endl;
    cout << "b数组的最小值为:" << min(b, 5) << endl;
       
    return 0;
}

#include <iostream>
#include <vector>
using namespace std;
int main()
{
    vector <int> v1;
    v1.push_back(1);
    v1.push_back(2);

    //迭代器 
    v1.insert(v1.begin(), 0);//头部插入
    v1.insert(v1.end(), 4);  //尾部插入 
    v1.insert(v1.end()-1, 3);//倒数第二位置     
    v1[4] = 10;  //v1[5] = 6;越界错误
    for (int i=0; i<v1.size(); i++) {
        cout << v1[i] << ' ';
    } 
    cout << endl;

    v1.pop_back();   //删除尾部 10 
    v1.erase(v1.begin()); //删除头 0 
    v1.erase(v1.begin(), v1.end()); //全删
    cout << "全删后：";  // v1.clear();
    for (int i=0; i<v1.size(); i++) {
        cout << v1[i] << ' ';
    }  
      
    vector <string> v;
    v.push_back("food");
    v.push_back("candy");
    v.push_back("apple");
    sort(v.begin(), v.end());
    vector <string>::iterator it; //迭代器 
    for (it=v.begin(); it!=v.end(); it++) {
        cout << *it << " ";    
    }
    cout << endl;    

    return 0;
}

#include <string.h>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
 
int main()
{
    vector<int> obj;               //创建一个向量存储容器 int(定义了一系列操作的动态数组
    
    for (int i=0; i<20; i++)       // push_back(elem)在数组最后添加数据 
    {
        obj.push_back(i);
        cout << obj[i] << ",";    
    }
    
    cout << "
max_size:" << obj.max_size() << ","; 
    cout << "
capacity:" << obj.capacity() << ",";  
    cout << "
size:" << obj.size() << ",";  
    cout << "
empty:" << obj.empty() << ",";  
    
    for (int i=0; i<5; i++)         //去掉数组最后一个数据 
    {
        obj.pop_back();
    }
       obj.push_back(10);
    obj.push_back(30);
    
    reverse(obj.begin(), obj.end()); //从大到小 
    cout << "
从大到小 :" << endl;
    for (int i=0; i<obj.size(); i++)
    {
        cout << obj[i] << ",";   
    } 
    cout << "
" << endl;
 
    cout << "从小到大:" << endl;
    sort(obj.begin(), obj.end()); //从小到大
    for (int i=0; i<obj.size(); i++)
    {
        cout << obj[i] << ",";   
    }    
    
    cout << "
清除容器:" << endl;
    obj.clear();   //清除容器中所以数据
    for (int i=0; i<obj.size(); i++)
    {
        cout << obj[i] << endl;
    }    
    
    cout<<"
"<<endl;
    cout << "实际数据个数 :" << endl;    
    for (int i=0; i<obj.size(); i++)  //size()容器中实际数据个数 
    {
        cout << obj[i] << ",";
    }
 
    //方法一 
       obj.push_back(112);
    obj.push_back(120);    
    obj.push_back(112); 
    cout << "直接利用数组："; 
    for (int i=0; i<obj.size(); i++)
    {
        cout << obj[i] << " ";
    }
    cout << ", obj[2]=" << obj[2];

    cout<<endl; 
    cout<<"利用迭代器：" ;
    //方法二，使用迭代器将容器中数据输出(就是指针)
    vector<int>::iterator it;//声明一个迭代器，来访问vector容器，作用：遍历或者指向vector容器的元素 
    for( it=obj.begin(); it != obj.end(); it++)
    {
        cout << *it << " ";
    }
    return 0;
}

/*  使用模板实现泛型类型的函数和类 */
#include <iostream>
#include <vector>
#include <cstdlib>
#include <string>
#include <stdexcept>
 
using namespace std;
 
template <class T>
class Stack { 
  private: 
    vector<T> elems;     // 元素 
 
  public: 
    void push(T const&);  // 入栈
    void pop();               // 出栈
    T top() const;            // 返回栈顶元素
    bool empty() const{       // 如果为空则返回真。
        return elems.empty(); 
    } 
}; 
 
template <class T>
void Stack<T>::push (T const& elem) 
{ 
    // 追加传入元素的副本
    elems.push_back(elem);    
} 
 
template <class T>
void Stack<T>::pop () 
{ 
    if (elems.empty()) { 
        throw out_of_range("Stack<>::pop(): empty stack"); 
    }
    // 删除最后一个元素
    elems.pop_back();         
} 
 
template <class T>
T Stack<T>::top () const 
{ 
    if (elems.empty()) { 
        throw out_of_range("Stack<>::top(): empty stack"); 
    }
    // 返回最后一个元素的副本 
    return elems.back();      
} 
/* 模板函数 */
template <typename T>
inline T const& Max (T const& a, T const& b) 
{ 
    return a < b ? b:a; 
} 

int main() 
{ 
    int i = 39;
    int j = 20;
    cout << "Max(i, j): " << Max(i, j) << endl; 
 
    double f1 = 13.5; 
    double f2 = 20.7; 
    cout << "Max(f1, f2): " << Max(f1, f2) << endl; 
 
    string s1 = "Hello"; 
    string s2 = "World"; 
    cout << "Max(s1, s2): " << Max(s1, s2) << endl; 
    
    
    try { 
        Stack<int>   intStack;  // int 类型的栈 
        Stack<string> stringStack;    // string 类型的栈 
 
        // 操作 int 类型的栈 
        intStack.push(7); 
        cout << intStack.top() <<endl; 
 
        // 操作 string 类型的栈 
        stringStack.push("hello"); 
        cout << stringStack.top() << std::endl; 
        stringStack.pop(); 
        stringStack.pop(); 
    } 
    catch (exception const& ex) { 
        cerr << "Exception: " << ex.what() <<endl; 
        return -1;
    } 
}

#include <iostream>
#include <stack>
#include <string>
#include <utility>
#include <map>
using namespace std;

int main()
{
    stack <int> s;
    s.push(1);    
    s.push(2);
    s.push(3);
    s.push(4);
    s.push(11);
    
    cout << "top of the stack:" << s.top() << endl;
    cout << "the number of elements:" << s.size() << endl;
    cout << "process of pop:" << endl;
    
    while (s.empty() != true) // stack isn't empty
    {   cout << "		";
        cout << s.top() << endl; //read the top of the stack    
        s.pop();  // pop, and delete the top
    }


    // key value
    map <int, string> StuInfo;
    StuInfo.insert(pair <int, string> (1, "Tom"));
    StuInfo.insert(pair <int, string> (5, "Jack"));
    StuInfo[2] = "Lily";
    StuInfo[7] = "Bruce";    
    map <int, string>::iterator it;   // 指针 
    
    for (it=StuInfo.begin(); it!=StuInfo.end(); it++)
    {
        cout << (*it).first << " " << (*it).second << endl;
    }    
        
    return 0;
}