STL中常用的c++语法

#include <iostream>
using namespace std;

template<class T>
struct Plus
{
    T operator()(const T& x, const T& y)const
    {
        return x + y;
    }
};

template<class T>
struct Minus
{
    T operator()(const T& x, const T& y)const
    {
        return x - y;
    }
};

int main()
{
    Plus<int>plusobj;
    Minus<int>minusobj;

    cout << plusobj(3, 4) << endl;
    cout << minusobj(3, 4) << endl;

    //以下直接产生仿函数的临时对象，并调用
    cout << Plus<int>()(43, 50) << endl;
    cout << Minus<int>()(43, 50) << endl;

    system("pause");
    return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

/*
template <class InputIterator,class Function>
Function for_each(InputIterator first, InputIterator last, Function f)
{
    for (; first != last; ++first)
    {
        f(*first);
    }
    return f;
}
*/

template <typename T>
class print
{
public:
    void operator()(const T& elem)
    {
        cout << elem << ‘ ‘ << endl;
    }
};

int main()
{
    int ia[6] = { 0,1,2,3,4,5 };
    vector<int>iv(ia, ia + 6);

    for_each(iv.begin(), iv.end(), print<int>());

    system("pause");
    return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

template <typename T>
class testClass
{
public:
    static const int a = 5;
    static const long b = 3L;
    static const char c = ‘c‘;
    static const double d = 100.1;
};

int main()
{
    cout << testClass<int>::a << endl;
    cout << testClass<int>::b << endl;
    cout << testClass<int>::c << endl;
    //下面的语句出错，带有类内初始值设定项的静态数据成员必须具有不可变的常量整型
    cout << testClass<int>::d << endl;

    system("pause");
    return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

class INT
{
    friend ostream& operator<<(ostream& os, const INT& i);
public:
    INT(int i) :m_i(i) {};
    //自增然后得到值
    INT& operator++()
    {
        ++(this->m_i);
        return *this;
    }
    //先得到值然后自增
    const INT operator++(int)
    {
        INT temp = *this;
        ++(this->m_i);
        return temp;
    }
    //取值
    int& operator*() const
    {
        return (int&)m_i;
        //下面的语句会出错，因为将int&类型的引用绑定到const int类型的初始值设定项
        //return m_i;
    }
private:
    int m_i;
};

ostream& operator<<(ostream& os, const INT& i)
{
    os << ‘[‘ << i.m_i << ‘]‘ << endl;
    return os;
}

int main()
{
    INT I(5);
    cout << I++;
    cout << ++I;
    cout << *I;

    system("pause");
    return 0;
}