How to run a simple objective-c in linux - objective-c

Question

EDITED
I have been trying to start coding in Objective-c. Its just a simple program to try getter and setter methods. Also print Hello World. THe following is my code:
#import <objc/Object.h>
#interface Car:Object{
int wheel: 5;
}
- (int)wheel;
- (void)setWheel: (int)newWheel;
#end
#include <stdio.h>
#implementation Car
- (int)wheel{
return wheel;
}
- (void)setWheel: (int)newWheel{
wheel = newWheel;
}
#end
#include <stdlib.h>
int main(void){
printf("Hello World");
}
I now get garbage
/tmp/cc3UC6jY.o: In function `__objc_gnu_init':
hello.m:(.text+0x6d): undefined reference to `__objc_exec_class'
/tmp/cc3UC6jY.o:(.data+0x1c0): undefined reference to `__objc_class_name_Object'
collect2: error: ld returned 1 exit status
I used the the command gcc -o hello hello.m -lobjc
I have spent hours googling this answer.

Answer 1

The following variation of your code compiled and ran for me:
#import <objc/Object.h>
#interface Car : Object {
int wheel;
}
- (int)wheel;
- (void)setWheel: (int)newWheel;
#end
#implementation Car
- init {
wheel = 5;
return self;
}
- (int)wheel {
return wheel;
}
- (void)setWheel: (int) newWheel {
wheel = newWheel;
}
#end
#include <stdio.h>
int main(void){
printf("Hello World\n");
id myCar = [[Car alloc] init];
printf("Wheel value is %d\n", [myCar wheel]);
return 0;
}