It looks like you didnt declare those variables this should fix it(untested)
// include the Dark GDK header file (http://forum.thegamecreators.com/?m=forum_read&i=22)
#include "DarkGDK.h"
// main entry point for the application
void DarkGDK ( void )
{
// PUT YOUR CODE HERE //
// create our variables (// means comment and gets ignored by C++)
char name[30]; // string (text) is held in a character array
char output[30];
int x = 0; // whole numbers are held in integer variables
int y = 0;
int newX = 0;
int newY = 0;
int radius = 0;
float cash = 0.0; // decimal numbers are held in float variables (“floating point”)
// get a string from the user
dbPrintC( "Enter your name: " ); // prompt
strcpy( name, dbInput() ); // copy the string input into the string variable
// get a decimal number (float) from the user
dbPrintC( "How much cash do you have? " ); // prompt
cash = atof( dbInput() );
// get whole numbers from the user
dbPrintC( "x: " );
x = atoi( dbInput() );
dbPrintC( "y: " );
y = atoi( dbInput() );
dbPrintC( "radius: " );
radius = atoi( dbInput() );
// calculate the values for the box
int boxLeft = x;
int boxTop = y + 100; // move down so box doesn’t cover the circle
int boxRight = boxLeft + 50; // box will be 50 pixels wide
int boxBottom = boxTop + 50; // box will be 50 pixels high
// draw the name and money
dbPrint( ); // blank line
dbPrint( "Output: " ); // heading
dbPrint( name ); // notice the “C” is missing in order to print a new line
dbPrintC( "$" ); // use the “C” here so the cursor waits at the end of the line
dbPrint( cash );
// draw text centered at the given coordinates
dbCenterText( x, y+10, name );
// draw text starting at the given coordinates
dbText(x , y+20, name );
// change the color
dbInk ( RGB(0,255,255), RGB(0,255,0) );
// draw some dots, a box, and a circle
// Single dot (single pixel): dbDox( x, y );
dbDot( x, y );
dbDot( x - 2, y );
dbDot( x + 2, y );
// Circle: dbCircle( centerX, centerY, radius);
dbCircle( x, y, radius );
// Line: dbLine ( startX, startY, endX, endY );
dbLine( x, y + 100, x + 50, y + 100 );
// Box: dbBox( left, top, right, bottom );
dbBox( x, y + 200, x + 50, y + 250 );
// pause
dbWaitKey();
// turn on sync rate and set the maximum rate to 60 fps (frames per second)
dbSyncOn ( );
dbSyncRate ( 60 );
// stop GDK from responding to the escape key
// so we can control what happens when escape key is pressed
dbDisableEscapeKey ( );
// our main game loop
while ( LoopGDK ( ) )
{
// ADD YOUR LOOP CODE HERE (REPEATING GAME CODE) //
// break out of the loop when escape key is pressed
if ( dbEscapeKey ( ) )
break;
// update the contents of the screen
dbSync ( );
}
// return back to Windows
return;
}