C 迭代器

标签：c++迭代器

#include <iostream> #include <cstdlib>
using namespace  std;
template<class T,int ssize=100>
class MyList
{  T data[ssize];
   int length;
   public:
	      MyList (){length=0;}
	      void push_back(const T&i)
	      {
           if(length>=ssize-1)exit(1);
           data[length++]=i;      
	      }
	      bool empty()
	      {
		      return(length==0);
	      }
       class iterator;
       friend class iterator;
       class iterator
          {
            MyList&lst;
            int index;
          public:
	          iterator(MyList &l):lst(l)
	             {
		              index=0;
	             }
              iterator(MyList &l,bool):lst(l)
	             {
		              index=l.length;
	             }
             T operator*() const
	             {
		             if(index>=0)
		               return lst.data[index];
		             else
		                exit(1);
	             }
              T operator++()
	             {
		             if(index>lst.length)
                        exit(2);
		               return lst.data[++index];	          
	             }
	           T operator++(int)
	             {
		             if(index>lst.length)
                        exit(3);
		               return lst.data[index++];	          
	             }
	             T operator--()
	             {
		             if(index<=0)
                        exit(4);
		               return lst.data[--index];	          
	             }
	             T operator--(int)
	             {
		             if(index<=0)
                        exit(5);
		               return lst.data[index--];	          
	             }
                bool operator!=(const iterator &rv)const
              {
	              return index!=rv.index;
              }
               bool operator==(const iterator &rv)const
              {
	              return index==rv.index;
              }
               bool operator<=(const iterator &rv)const
              {
	              return index<=rv.index;
              }
               bool operator<(const iterator &rv)const
              {
	              return index<rv.index;
              }
               bool operator>=(const iterator &rv)const
              {
	              return index>=rv.index;
              }
               bool operator>(const iterator &rv)const
              {
	              return index>rv.index;
              }
          };
	   iterator begin()
	   {
		   return iterator(*this);
	   }
	   iterator end()
	   {
		   return iterator(*this,true);
	   }
};
int main()
{
	MyList<int> lst;
	lst.push_back(1);
	lst.push_back(2);
	lst.push_back(3);
	lst.push_back(4);
	MyList<int>::iterator iter=lst.begin();
    cout<<"从表头到表尾：";
    for (; iter!=lst.end();iter++)  
       cout<<*iter<<" ";
       cout<<endl;	
       MyList<int>::iterator iterl=lst.end();
    cout<<"从表尾到表头：";
    iterl--;
    for (; iterl>=lst.begin();iterl--)  
       cout<<*iterl<<" ";
       cout<<*iterl<<endl;	 
}

C 迭代器

标签：c++迭代器

原文地址：http://wzsts.blog.51cto.com/10251779/1758659