text: class window
  {
   private:
    char str[1921];
    int pos;
   public:
   
   window()
   {
    memset(str,0x00,1920);
   }
   
   window(char *s)
   {
    str[1920]=0;
    memset(str,*s,1920);
   }
   
   
   void print()
   {
    cout<<str;
   }
   
   
   void clear()
   {
    memset(str,0,1920);
   }
   
   void change(const char *c)
   {
    memset(str,*c,1920);
   }
   
   void change(int row,int col,const char *c)
   {
    pos=80*row+col;				//80x+y where x is row and y is column.
    str[pos]=*c;
   }
   
   
   
   void change(void (*callback)(int,int,char&))
   {
    int i,j;
    char c;
    
    for(i=0;i<24;i++)
    {
     for(j=0;j<80;j++)
     {
      callback(i,j,c);
      if(c!='\0')
      {
       pos=80*i+j;
       str[pos]=c;
   }}}}
  };