#include<iostream.h>
    #include<stdlib.h>
    typedef int Elemtype;
    struct List{
        Elemtype*list;
        int size;
        int MaxSize;
    };
   
    void main()
    {
        int a[4]={3,6,9,12};
        int i;
        ElemType x;
        List t;
        InitList(t);
        for(i=0;i<12;i++)
        InsertList(t,a[i],i+1);
        InsertList(t,18,5);
        TraverseList(t);
        cout<<"按值插入，输入待插入元素的值:";
        cin>>x;
        if(InsertList(t,x,0))
         cout<<"插入成功!"<<end1;
        else cout<<"插入失败!"<<end1;
        TraverseList(t);
    }
 
    void InitList(List &L)
    {
        L.MaxSize=20;
        L.list=new ElemType[L.MaxSize];
        if(L.list==NULL)
        {
            cout<<"动态可分配的存储空间用完，退出运行!"<<endl;
                exit(1);
        }
            L.size=0;
    }
   
    bool InsertList(List &L,ElemType item,int pos)
    {
        if(pos<-1||pos>L.size+1){
            cout<<"pos值无效！"<<end1;return false;
        }
        
        int i;
        if(pos==0) {
            for(i=0;i<L.size;i++)
            if(item<L.size[i]) break;
            pos=i+1;
        }
        
        else if(pos==-1) pos=L.size+1;
        
        if(L.size==L.MaxSize) {
            int k=sizeof(Elemtype);
            L.list=(Elemtype*)realloc(L.list,2*L.Maxsize*k);
            
            if(L.list==NULL) {
                cout<<"动态可分配的储存空间已用完，退出运行！"<<end1;
                exit(1);
            }
            L.Maxsize=2*L.Maxsize;
        }
        
   
        for(i=L.size-1;i>=pos-1;i--)
           L.list[i+1]=L.list[i];
           
           L.list[pos-1]=item;
           
           L.size++;
           
           return true;
    }
   
    void TraverseList(List &L)
    {
        for(int i=0;i<L.size;i++)
            cout<<L.list[i]<<' ';
        cout<<endl;
    }


1    22    C:\Users\Administrator\Desktop\main111.cpp    [Error] iostream.h: No such file or directory
compilation terminated.

添加什么头文件？？