[C++][STL] binary_search

所需的页眉
   <algorithm>
				
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原型
   template<class ForwardIterator, class T> inline
       ForwardIterator upper_bound(ForwardIterator first,
                                   ForwardIterator last,
                                   const T& value)
				
注： 在原型中的类/参数名称与在头文件中的与原始版本不匹配。他们已被修改，以提高可读性。
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说明
upper_bound 算法将最后一个位置返回序列中的序列的顺序进行维护，可以在插入值。 

upper_bound 返回迭代器放在该位置的值可将插入在范围 [第一次...最后一次），或如果没有此类位置存在，则返回上一次。 

upper_bound 假定范围 [第一次...最后一次） 进行排序使用运算符 <。
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示例代码
////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: /GX
// 
// upper_bound.cpp : Illustrates how to use the upper_bound
//                   function.
// 
// Functions:
// 
//    upper_bound : Return the upper bound within a range.
// 
// Written by Kalindi Sanghrajka
// of Microsoft Product Support Services,
// Software Core Developer Support.
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
////////////////////////////////////////////////////////////////////// 

// disable warning C4786: symbol greater than 255 character,
// okay to ignore
#pragma warning(disable: 4786)

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

void main()
{
    const int VECTOR_SIZE = 8 ;

    // Define a template class vector of int
    typedef vector<int, allocator<int> > IntVector ;

    //Define an iterator for template class vector of strings
    typedef IntVector::iterator IntVectorIt ;

    IntVector Numbers(VECTOR_SIZE) ;

    IntVectorIt start, end, it, location ;

    // Initialize vector Numbers
    Numbers[0] = 4 ;
    Numbers[1] = 10;
    Numbers[2] = 10 ;
    Numbers[3] = 30 ;
    Numbers[4] = 69 ;
    Numbers[5] = 70 ;
    Numbers[6] = 96 ;
    Numbers[7] = 100;

    start = Numbers.begin() ;   // location of first
                                // element of Numbers

    end = Numbers.end() ;       // one past the location
                                // last element of Numbers

    // print content of Numbers
    cout << "Numbers { " ;
    for(it = start; it != end; it++)
        cout << *it << " " ;
    cout << " }\n" << endl ;

    //return the last location at which 10 can be inserted
    // in Numbers
    location = upper_bound(start, end, 10) ;

    cout << "Element 10 can be inserted at index "
        << location - start << endl ;
}
				
程序输出为：
Numbers { 4 10 10 30 69 70 96 100  }

Lower_bound 和 upper_bound的区别

lower_bound: the position that found is the first pos which value is not lower than compare value
upper_bound: the position that found is the first pos which value is larger than compare value
例子：

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#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
 
int main()
{
  int A[] = { 1, 2, 3, 3, 3, 5, 8 };
  const int N = sizeof(A) / sizeof(int);
 
  for (int i = 1; i <= 10; ++i) {
    int * p = upper_bound(A, A + N, i);
    int * q = lower_bound(A,A+N,i);
    cout << "Searching for " << i << ".  "<<endl;
    cout << "upper_bound Result: index = " << p - A << ", "<<endl;
    cout << "lower_bound Result: index = " << q - A << ", "<<endl;
    if (p != A + N)
    {
      cout << "upper_bound A[" << p - A << "] == " << *p << endl;
      cout << "lower_bound A[" << q - A << "] == " << *q << endl;
    }
    else
      cout << "which is off-the-end." << endl;
    cout<<"--------------------------------"<<endl;
  }
  return 0;
}

 if (keyScopeItem.getEnableAggregation())
    {
        bool isMatch = false;
        ScopeStartEndValuesMap::const_iterator upperIter = keyScopeItem.getKeyScopeValues().upper_bound(keyScopeItem.getAggregateKeyValue());
        if ( upperIter != keyScopeItem.getKeyScopeValues().begin() )
        {
            --upperIter;
            
            if ( keyScopeItem.getAggregateKeyValue() >= upperIter->first 
            && keyScopeItem.getAggregateKeyValue() <=  upperIter->second )
            {
                isMatch = true;
            }
        }

        // will match...
        if ( isMatch )
        {
            eastl::string msg;
            msg.sprintf("[StatsConfigData].parseKeyScopeItem(): key scope item [%s] has non-unique aggregate key value [%"PRId64"]",
                keyScopeItemName, keyScopeItem.getAggregateKeyValue());
            TdfString& str = validationErrors.getErrorMessages().push_back();
            str.set(msg.c_str());
            return false;
        }
    }