custom console menu in c++

Question

Hello everyone,
     My question is:Arrow pointing to an invalid area.Details can be viewed in the attachment to the operation of the demonstration.
my code is as follows:


#include <iostream>
#include <string>
#include <conio.h>
using namespace std;


/* direction keys */
#define  KEY_UP 72
#define  KEY_DOWN 80
#define  KEY_LEFT 75
#define  KEY_RIGHT 77


static int POINTER_TO_ROW=0;
static int POINTER_TO_COLUMN=0;
const string menu_name[4][4]={"Menu1","Menu2","Menu3","Menu4","Menu5","Menu6","Menu7","Menu8"};
string menu_name_t[4][4]={"Menu1","Menu2","Menu3","Menu4","Menu5","Menu6","Menu7","Menu8"};
const string flag="->";
int i=0,j=0,k=0,newline=0;


/* Function prototypes */
void menu();
void reset_menu_name_t();


int main()
{
char Key='Y';
menu();
system("color 16"); /* Setting up the console background and foreground colors */


    while (toupper(Key)!='N')
    {

Key=getch();  /* get current direction keys */

switch(Key)
{
 case 72: /* UP */
system("cls");
POINTER_TO_ROW--;
menu();
break;
     case 80: /* DOWN */
system("cls");
POINTER_TO_ROW++;
menu();
break;
 case 75: /* LEFT */
 /**/
 break;
 case 77: /* RIGHT */
/**/
 break;
}
    }
return 0;
}


void reset_menu_name_t()
{
for(j=0;j<4;j++)
{
for (k=0;k<4;k++)
{
menu_name_t[j][k]="";
   menu_name_t[j][k]=menu_name[j][k];
}
     
}
   
}
void menu()
{
if(POINTER_TO_ROW>3) POINTER_TO_ROW=0;
if(POINTER_TO_ROW<0) POINTER_TO_ROW=3;
    menu_name_t[POINTER_TO_ROW][POINTER_TO_COLUMN]=flag+menu_name_t[POINTER_TO_ROW][POINTER_TO_COLUMN];
cout<<"\n\n\n\n";
newline=0;
for (i=0;i<4;i++)
{
for (k=0;k<4;k++)
{ 
 if(newline%2==0) cout<<"\n";
 if(i==POINTER_TO_ROW&&k==POINTER_TO_COLUMN)cout<<"\t\b\b"<<menu_name_t[i][k]<<"\t";
 else cout<<"\t"<<menu_name_t[i][k]<<"\t";


 newline++;
}
}


cout<<"\n\n\tEnter N to exit program."<<'\n';
reset_menu_name_t();
}




Regards,

Ken 

thank very much. :)