常用STL算法1_遍历

#define _CRT_SECURE_NO_WARNINGS#include <iostream>#include <vector>#include <list>#include <algorithm>#include <functional>#include <string>#include <iterator> //输出流using namespace std;//函数对象struct MyShow{public:    MyShow()    {        m_count = 0;    }    void operator()(const int & elem)    {        cout<<elem<<" ";        m_count++;    }    void printCount()    {        cout<<"m_count:"<<m_count<<endl;    }private:    int m_count;};//一般情况下，for_each所使用的函数对象，参数是引用，没有返回值//回调函数void show(const int &iItem){    cout << iItem << " ";}//for_eachvoid main061_for_each(){    int iArray[] = {1,2,3,4,5};    vector<int> vecInt(iArray,iArray+sizeof(iArray)/sizeof(iArray[0]));    //1. 回调函数    for_each(vecInt.begin(), vecInt.end(), show);    cout<<endl;    //2. 函数对象    for_each(vecInt.begin(), vecInt.end(), MyShow());    cout<<endl;    //3. 函数对象可以记录状态  for_each返回值：_Fn1 for_each(_InIt _First, _InIt _Last, _Fn1 _Func)    MyShow myshow;    //for_each(vecInt.begin(), vecInt.end(), myshow);//no_ok    //myshow = for_each(vecInt.begin(), vecInt.end(), myshow);//ok    myshow = for_each(vecInt.begin(), vecInt.end(), MyShow());//ok    cout<<endl;    cout<<endl;    myshow.printCount();    /*    _Fn1 for_each(_InIt _First, _InIt _Last, _Fn1 _Func)    {   // perform function for each element        _DEBUG_RANGE(_First, _Last);        _DEBUG_POINTER(_Func);        _For_each(_Unchecked(_First), _Unchecked(_Last), _Func);        return (_STD move(_Func));    }    */}//Transform所使用的函数对象，参数一般不使用引用，而是使用元素，并且有返回值int op_increase2 (int i) { return ++i; }  int op_sum2 (int i, int j) { return i+j; }  template <typename T>void printVectorElem(T &v){    T::iterator it;    for (it=v.begin(); it!=v.end(); ++it)     {        cout <<*it <<" ";      }    cout << endl; }//transform 两种应用void main062_transform(){    vector<int> first;      vector<int> second;      vector<int>::iterator it;      // 1.set some values:      for (int i=1; i<6; i++)    {        first.push_back (i*10); //  first: 10 20 30 40 50      }    second.resize(first.size());     // allocate space      //2. 一元函数 回调    //_OutIt transform(_InIt _First, _InIt _Last, _OutIt _Dest, _Fn1 _Func)    // transform [_First, _Last) with _Func    transform (first.begin(), first.end(), second.begin(), op_increase2);  //回调    // second: 11 21 31 41 51      //2. 二元函数 回调    //_OutIt transform(_InIt1 _First1, _InIt1 _Last1,_InIt2 _First2, _OutIt _Dest, _Fn2 _Func)    // transform [_First1, _Last1) and [_First2, ...) with _Func    transform (first.begin(), first.end(), second.begin(), first.begin(), op_sum2); //回调    //  first: 21 41 61 81 101      cout << "first contains:";      printVectorElem(first);;      //3. 预定义函数对象    /*    struct negate: public unary_function<_Ty, _Ty>    {   // functor for unary operator-        _Ty operator()(const _Ty& _Left) const        {   // apply operator- to operand            return (-_Left);        }    };    */    transform(first.begin(), first.end(), first.begin(), negate<int>());    cout<<"负数：";    printVectorElem(first);    //4. 函数适配器    list<int> list1;    list1.resize(first.size());    /*    struct multiplies: public binary_function<_Ty, _Ty, _Ty>    {           // functor for operator*        _Ty operator()(const _Ty& _Left, const _Ty& _Right) const        {               // apply operator* to operands            return (_Left * _Right);        }    };    */    transform(first.begin(), first.end(), list1.begin(), bind2nd(multiplies<int>(),10));    cout<<"适配器（x10）：";    printVectorElem(list1);    //5 输出到屏幕  ostream_iterator<int>(cout, " ")    transform(first.begin(),first.end(),ostream_iterator<int>(cout, " "), negate<int>());}void main063_for_each_pk_transform(){    //一般情况下，for_each所使用的函数对象，参数是引用，没有返回值    //Transform所使用的函数对象，参数一般不使用引用，而是使用元素，并且有返回值    /* transform()所需要的函数对象要求有返回值*/    /*    _OutIt _Transform(_InIt _First, _InIt _Last, _OutIt _Dest, _Fn1 _Func)    {           // transform [_First, _Last) with _Func        for (; _First != _Last; ++_First, ++_Dest)        {            *_Dest = _Func(*_First);//返回值        }        return (_Dest);    }    */}int main(){    //main061_for_each();    main062_transform();    main063_for_each_pk_transform();    cout<<"\nhello"<<endl;    system("pause");    return 0;}