Thread: explaination coding for my viva!!! urgent!!!

hello all!!! i need your help to explain these codes for me because i may need to viva soon....thanks!!!

1.) here are codes, i am using arrow keys to control my menu...as i know the 72 is for arrow key up and 80 is for arrow key down. but y do need the function below that add 256 to my arrows code???

Code:

int get_code ( void )
{
  int ch = getch();
 if ( ch == 0 || ch == 224 )
           ch = static_cast<int>(256 + getch());
  return ch;
}

while ( ( ch = get_code() ) != 27 )
{
switch ( ch ) {
case 256 + 72://arrow key up}
}

2. )i also use the code below to change the particular line of my program to make it look more attractive. but i dun really understand wat does the handle h mean. wat is the h??

Code:

int main ( void )
{
  HANDLE h = GetStdHandle ( STD_OUTPUT_HANDLE );//line 1
  WORD wOldColorAttrs;//line2
  CONSOLE_SCREEN_BUFFER_INFO csbiInfo; //line3
  
    GetConsoleScreenBufferInfo(h, &csbiInfo);//line4
  wOldColorAttrs = csbiInfo.wAttributes; //line5
  
   SetConsoleTextAttribute ( h, FOREGROUND_RED | FOREGROUND_INTENSITY );
  
  printf ( "This is a test\n" );

  SetConsoleTextAttribute ( h, FOREGROUND_BLUE| FOREGROUND_INTENSITY );
  
  printf ( "This is a test\n" );
   SetConsoleTextAttribute ( h, wOldColorAttrs);
  return 0;
}

is anyone out there can explain line 1, 2, 3, 4 and 5 for me?? thanks!!

thanks guys first.....ur guys will give me a big help on my viva....thanks!!!

1. getch() returns 0 the first time called when a special key is presses, such as arrow and function keys. When that happens the program must call getch() a second time to get the actual key code. If get_code() simply returned that key code, the calling function would have no way to distinguish arrow keys from any other key. There are a couple (maybe more) ways to handle that, and get_code() adds 256 to special key code. Now the calling function only needs to check if its return value > 256 to determine whether the key was a special key or not. If 72 is an up arrow, then get_code() will return 256+72.

2. HANDLE is a data type defined in windows.h. Apparently you are completly new to MS-Windows win32 api programming, so I would suggest reading this tutorial before continuing. win32 api programming is just simply too difficult and complicated to spoonfood in these forums.