【c++算法】移除性算法

根据元素值或某一条件，在区间内移除某些元素

 

Remove	将等于某特定值得元素全部移除
Remove_if	将满足条件的元素全部移除
Remove_copy	将不等于某一特定值得元素全部复制到它处
Remove_copy_if	将不满足条件的元素全部复制到它处
Unique	移除比邻的重复数据
Unique_copy	移除比邻的重复数据，并复制到它处

#include <iostream>
#include <vector>
#include <algorithm>
#include <list>
#include <iterator>

using namespace std;

template<class T>
class FunctionObjectType
{
private:
    T theValue;
public:
    FunctionObjectType(const T& v):theValue(v)
    {

    }
public:
    void operator()(T &i)
    {
        i += theValue;
    }
};
/*--------------打印元素-------------*/
template<class T>
inline void PrintElements(const T& coll,const char* optcstr="")
{
    typename T::const_iterator pos;

    std::cout<<optcstr;
    for(pos=coll.begin();pos != coll.end(); ++pos)
        std::cout<<*pos<<" ";

    std::cout<<std::endl;
}

template<class T>
inline void PrintElementsPos(const T& coll,const char* optcstr="")
{
    typename T::const_iterator pos;

    std::cout<<optcstr;
    for(pos=coll.begin();pos != coll.end(); ++pos)
        std::cout<<&*pos<<" ";

    std::cout<<std::endl;
}

/*--------------插入int型数据------------------*/
template<class T>
inline void InsertElements(T& coll,int first,int last)
{
    for(int i = first; i<=last; ++i)
        coll.insert(coll.end(),i);
}

void print(int elem)
{
    std::cout<< elem << " ";
}

void Learn_remove()
{
    std::cout<<endl<<"--------------------in Learn remove() remove_if()"<<endl
                             <<"                            in Learn remove_copy() remove_copy_if()"<<endl
                             <<"                            in Learn unique() unique_copy()"
                             <<std::endl;

    vector<int> coll;
    InsertElements(coll,2,6);
    InsertElements(coll,4,9);
    InsertElements(coll,1,7);
    PrintElements(coll,"coll : ");
    PrintElementsPos(coll,"coll : ");

    vector<int>::iterator pos;
    std::cout<<"remove是逻辑上的删除，将被删除的元素移动到容器末尾"<<endl;
    pos = remove(coll.begin(),coll.end(),5);
    PrintElements(coll,"coll : ");
    PrintElementsPos(coll,"coll : ");
    std::cout<<"pos : " << *pos<<endl;
    std::cout<<"erase一般作为一个container的成员函数，是真正删除的元素，是物理上的删除"<<endl;
    coll.erase(pos,coll.end());
    PrintElements(coll,"coll erase : ");

    std::cout<<"移除小于4的元素 : " <<endl;
    coll.erase(remove_if(coll.begin(),coll.end(),
                                   bind2nd(less<int>(),4)),
                                   coll.end());
    PrintElements(coll,"coll : ");

    std::cout<<"使用remove_copy移除值为4的元素拷贝到cout : " <<endl;
    remove_copy(coll.begin(),coll.end(),
                        ostream_iterator<int>(cout," "),
                        4);
    std::cout<<endl;

    std::cout<<"使用remove_copy_if移除值大于7的元素拷贝到cout : " <<endl;
    remove_copy_if(coll.begin(),coll.end(),
                        ostream_iterator<int>(cout," "),
                        bind2nd(greater<int>(),7));
    std::cout<<endl;

    int source[] = {1,4,4,6,1,2,2,3,1,6,6,6,6,5,7,5,4,4};
    int count = sizeof(source)/sizeof(source[0]);
    coll.clear();

    copy(source,source+count,back_inserter(coll));
    PrintElements(coll,"coll init : ");

    std::cout<<"移除与前一个值相等的元素，逻辑移除"<<endl;
    pos = unique(coll.begin(),coll.end());
    PrintElements(coll,"coll : ");
    coll.erase(pos,coll.end());
    PrintElements(coll,"coll erase : ");

    coll.clear();
    copy(source,source+count,back_inserter(coll));
    PrintElements(coll,"coll init : ");
    std::cout<<"移除比前一个值小的元素，逻辑移除"<<endl;
    pos = unique(coll.begin(),coll.end(),greater<int>());
    PrintElements(coll,"coll : ");
    coll.erase(pos,coll.end());
    PrintElements(coll,"coll erase : ");

    std::cout<<"使用unique_copy拷贝到cout : " <<endl;
    unique_copy(coll.begin(),coll.end(),
                        ostream_iterator<int>(cout," ")
                        );
    std::cout<<endl;

    coll.clear();
    copy(source,source+count,back_inserter(coll));
    PrintElements(coll,"coll init : ");
    std::cout<<"移除比前一个值小的元素，拷贝到cout : " <<endl;
    unique_copy(coll.begin(),coll.end(),
                        ostream_iterator<int>(cout," "),
                        greater<int>());
    std::cout<<endl;
}

int main()
{
    cout<<"hello world"<<endl;

    //--------------------移除性算法--------begin
    Learn_remove();
    //cin.get();

    return 0;
}