Problem with gcc in Leopard terminal

Question

Hi,
I am hoping to study computer science in college and eventually become a mac developer. I just recently bought an objective C programming book that is geared toward beginners. After reading it some, I tried to make a very simple program. I used text edit and saved it as a .m file. When I tried to compile it in terminal using gcc, (I have installed the dev tools) it spat back this error message.
+Undefined symbols:+
+".objcclass_nameObject", referenced from:+
+.objcclass_nameFraction in ccG8DljJ.o+
+"objcmsgSend", referenced from:+
+_main in ccG8DljJ.o+
+_main in ccG8DljJ.o+
+_main in ccG8DljJ.o+
+_main in ccG8DljJ.o+
+_main in ccG8DljJ.o+
+_main in ccG8DljJ.o+
+ld: symbol(s) not found+
+collect2: ld returned 1 exit status+
My program (below) follows one in the book very closely and I am sure the code is sound.
Any help would be appreciated.
Thanks!
+#import <stdio.h>+
+#import <objc/Object.h>+
+@interface Point: Object+
+int xcor;+
+int ycor;+
+-(void) setxcor: (int) x;+
+-(void) setycor: (int) y;+
+-(int) getxcor;+
+-(int) getycor;+
@end
+@implementation Point;+
+-(void) setxcor: (int) x+
+xcor = x;+
+-(void) setycor: (int) y+
+ycor = y;+
+-(int) getxcor+
+return xcor;+
+-(int) getycor+
+return ycor;+
@end
+int main (int argc, char *argv[])+
+Point *mypoint = [[Point alloc] init];+
+[mypoint setycor: 100];+
+[mypoint setxcor: 50];+
+printf("The point's coordinates are (%i,%i)\n",[mypoint getxcor], [mypoint getycor]);+
+[mypoint free];+
+return 0;+

Answer 1

Through gcc in terminal. I typed in the following: "gcc ~/Desktop/testprog/main.m -o ~/Desktop/testprog/proj1 -1 -ObjC ." The first directory is that of the source file and the last one is that of the target file (i.e. the finished command line app). I am not sure what significance the "-o" and "-1" arguments have.