STL源码剖析之算法：equal

template <class InputIterator, class BinaryPredicate>                             
inline bool equal(InputIterator first1, InputIterator last1, InputIterator first2, 
          BinaryPredicate binary_pred) {                                          
    for(; first1 != last1; ++first1, ++first2) {                                  
        if(!binary_pred(*first1, *first2))                                        
            return false;                                                         
    }                                                                             
    return true;                                                      
}