在这段代码中，我将 numitems 声明为静态变量，并初始化了类的超大尺寸。因为我认为这是错误的主要原因，(return (numitems==order-1));但这里也是与相关的问题(childarrray[0]==NULL)，完全这段代码取自 Java 并转换为 C++，所以我添加了指针而不是引用。请帮助修复我的代码中的错误。
#include<iostream>
#include<cstring>
using namespace std;
class data
{
public:
long ddata;
data(long dd)
{
ddata=dd;
}
void display()
{
cout<<ddata<<" ";
}
};
class Node
{
private:
//public:
static const int order=4;
static int numitems;
Node *parent;
Node *childarray[order];
data *item[order-1];
public:
Node(){}
public:
void connect(int childnum,Node *child)
{
childarray[childnum]=child;
if(child!=NULL)
child->parent=(this);
}
//disconetc from this node,return it;
Node *disconnectchild(int childnum)
{
Node *tempnode=childarray[childnum];
childarray[childnum]=NULL;
return (tempnode);
}
Node *getchild(int childnum){
return childarray[childnum];
}
Node *getparent()
{
return parent;
}
bool isleaf()
{
return ((childarray[0]==NULL)?true:false);
}
int getnumitems()
{
return numitems;
}
data *getitem(int index)
{
return item[index];
}
bool isfull()
{
return (numitems==(order-1));
}
int finditem(long key)
{
for(int j=0;j<order-1;j++)
{
if(item[j]==NULL)
break;
else if(item[j]->ddata==key)
return j;
}
return -1;
}
int insertitem(data *newitem)
{
if(numitems==order-1)
return 0;
numitems++;
long newkey=newitem->ddata;
for(int j=order-2;j>=0;j--)
{
if(item[j]==NULL)
continue;
else
{
long itskey=item[j]->ddata;
if(newkey<itskey)
item[j+1]=item[j];
else
{
item[j+1]=newitem;
return j+1;
}
}
}
item[0]=newitem;
return 0;
}
data *removeitem()
{
data *temp=item[numitems-1];
item[numitems-1]=NULL;
numitems--;
return temp;
}
void displayNode()
{
for(int j=0;j<numitems;j++)
item[j]->display();
cout<<endl;
}
};
int Node::numitems=0;
class tree234
{
Node *root;
public:
tree234() : root(NULL) {}
void displaytree()
{
recursivdisplay(root,0,0);
}
void recursivdisplay(Node *thisnode,int level,int childnum)
{
thisnode->displayNode();
int numitems=thisnode->getnumitems();
for(int j=0;j<numitems+1;j++)
{
Node *nextnode=thisnode->getchild(j);
if(nextnode!=NULL)
recursivdisplay(nextnode,level+1,j);
else
return ;
}
}
Node *getnextchild(Node *theNode,long thevalue)
{
int j;
int numItems=theNode->getnumitems();
for(j=0;j<numItems;j++)
{
if(thevalue<theNode->getitem(j)->ddata)
return theNode->getchild(j);
}
return theNode->getchild(j);
}
void split(Node * thisnode)
{
data *itemb,*itemc;
Node *parent,*child2,*child3;
int itemindex;
itemc=thisnode->removeitem();
itemb=thisnode->removeitem();
child2=thisnode->disconnectchild(2);
child3=thisnode->disconnectchild(3);
Node *newright=new Node();
if(thisnode==root)
{
root=new Node();
parent=root;
root->connect(0,thisnode);
}
else
parent=thisnode->getparent();
//deal with parent
itemindex=parent->insertitem(itemb);
int n=parent->getnumitems();
for(int j=n-1;j>itemindex;j--)
{
Node *temp=parent->disconnectchild(j);
parent->connect(j+1,temp);
}
parent->connect(itemindex+1,newright);
//deal with newright
newright->insertitem(itemc);
newright->connect(0,child2);
newright->connect(1,child3);
}
public:
void insert(long dvalue)
{
Node *curnode=root;
data *tempitem=new data(dvalue);
while(true)
{
if(curnode->isfull())
{
split(curnode);
curnode=curnode->getparent();
curnode=getnextchild(curnode,dvalue);
}
else if(curnode->isleaf())
break;
else
curnode=getnextchild(curnode,dvalue);
}
curnode->insertitem(tempitem);
}
public:
int find(long key)
{
Node *curnode=root;
int childnum;
while(true)
{
if((childnum=curnode->finditem(key))!=-1)
return childnum;
else if(curnode->isleaf())
return -1;
else
curnode=getnextchild(curnode,key);
}
}
};
char Getchar()
{
char AB;
cin>>AB;
return AB;
}
int main()
{
int found;
long value;
tree234 *thetree=new tree234();
thetree->insert(50);
thetree->insert(40);
thetree->insert(60);
thetree->insert(30);
thetree->insert(70);
while(true)
{
cout<<" enter first letter "<<endl;
cout<<" show ,insert or find : "<<endl;
char choice=Getchar();
switch(choice)
{
case 's':
cout<<" display tree ";
thetree->displaytree();
break;
case 'i':
cout<<" enter value to insert "<<endl;
cin>>value;
thetree->insert(value);
break;
case 'f' :
cout<< "enter value to find ";
cin>>value;
found=thetree->find(value);
if(found!=-1)
cout<<" found = "<<value<<endl;
else
cout<< " not found " <<value <<endl;
break;
default:
cout <<" invalid entry "<<endl;;
}
}
delete thetree;
return 0;
}