Windows STL算法学习一 find与find_if

先说#include "algostuff.h" 函数

#ifndef ALGOSTUFF_H
#define ALGOSTUFF_H

#include <iostream>
#include <vector>
#include <list>
#include <deque>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <functional>
#include <numeric>

//print all the elements
template <class T>
inline void PRINT_ELEMNTS(const T &col,const char *optcstr = " ")
{
    typename T::const_iterator pos;
    cout << optcstr;
    for(pos = col.begin();pos != col.end();++pos)
        cout << *pos << " ";
    cout << endl;
}

//insert values from first to last into the collection
template <class T>
inline void INSERT_ELEMENTS(T &col,int first,int last)
{
    for(int i = first;i <= last;++i)
        col.insert(col.end(),i);
}

#endif

find算法

template<class InputIterator, class T>
  InputIterator find ( InputIterator first, InputIterator last, const T& value )
  {
    for ( ;first!=last; first++) if ( *first==value ) break;
    return first;
  }

返回区间[first,end)中第一个值等于value的元素的位置。

如果没有找到匹配元素，则返回end。

list<string> Fruit;
list<string>::iterator FruitIterator;

Fruit.push_back("Apple");
Fruit.push_back("Pineapple");
Fruit.push_back("Star Apple");

FruitIterator = find (Fruit.begin(), Fruit.end(),"Pineapple");

//如果没找到，则返回end
    if (FruitIterator == Fruit.end()) {
       cout << "Fruit not found in list" << endl;
    }
    else {
       cout<< *FruitIterator <<endl;
    }

find_if()算法

template<class InputIterator, class Predicate>  
InputIterator find_if ( InputIterator first, InputIterator last, Predicate pred )  、

{  
    for ( ; first!=last ; first++ ) if ( pred(*first) ) break;  
    return first;  

} 

它在区间[first,end)中搜寻使一元判断式pred为true的第一个元素。

如果没找到，返回end。

#include "algostuff.h"

using namespace std;

int main()
{
    vector<int> intVec;

    INSERT_ELEMENTS(intVec,1,9);

    vector<int>::iterator pos;
    pos = find_if(intVec.begin(),intVec.end(),
        not1(bind2nd(modulus<int>(),3)));

    if(pos != intVec.end())
        cout << "The value divided by 3 exists,and the first value's position is " <<
        distance(intVec.begin(),pos) + 1 << endl;
    else
        cout << "The value divided by 3 not found!" << endl;
}