vector向量容器元素排序与查找

#include <algorithm>
#include <vector>

vector<int> vec;
//比较函数，这里的元素类型要与vector存储的类型一致
bool compare(int a,int b)
{
  return a<b; //升序排列
}

std::sort(vec.begin(),vec.end(),compare);

template <class RandomAccessIterator>
  void sort (RandomAccessIterator first, RandomAccessIterator last);

template <class RandomAccessIterator, class Compare>
  void sort (RandomAccessIterator first, RandomAccessIterator last, Compare comp);

vector<int> vec;
int a=10;
vector<int>::iterator it=find(vec.begin(),vector.end(),a);

template <class InputIterator, class T>
   InputIterator find (InputIterator first, InputIterator last, const T& val);

struct Element{
public:
    int a;
    int b;

    Element(int a,int b){
        this->a=a;
        this->b=b;
    };

    bool operator==(const Element& ele){
        return a==ele.a&&b==ele.b;
    };
};

//自定义比较函数
bool compare(const Element& left,const Element& right){
    return left.a<right.a; //升序排列
}

//重载输出操作符<<，格式化输出Element
ostream& operator<<(ostream& coutU,const Element& ele){
    coutU<<"a:"<<ele.a<<",b:"<<ele.b;
    return coutU;
}

int main(){
    vector<Element> vecEle;
    vecEle.push_back(Element(4,4));
    vecEle.push_back(Element(1,1));
    vecEle.push_back(Element(2,2));
    vecEle.push_back(Element(3,3));

    //sort
    std::sort(vecEle.begin(),vecEle.end(),compare);
    for(int i=0;i<vecEle.size();++i){
        cout<<vecEle[i]<<endl;
    }

    //查找Element(4,4)
    vector<Element>::iterator it=find(vecEle.begin(),vecEle.end(),Element(4,4));
    cout<<"found "<<*it<<endl;
}