Question

My project have no visible error but when i try to run it gives following error

Undefined symbols for architecture i386:
  "_OBJC_CLASS_$_ConcreteScreen", referenced from:
      objc-class-ref in ViewController.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I am using my ContactScreen class in ViewController.m

i tried by @class ContactScree and #import "ContactScreen.h"

and in my ViewController i am using it as [ContactScreen myMethod];
when i comment out this line it work fine but now it is giving compile time error 🙁
yesterday it was wroking fine

here is my code

#import "ViewController.h"


#import "ConcreteScreen.h"
@interface ViewController ()

@end

@implementation ViewController




-(IBAction)btnContactPress:(id)sender{
   NSLog(@"Contact Screen");

    ConcreteScreen *coontact = [[ConcreteScreen alloc]init];

}

Answer 1

You confused ConcreteScreen and ContactScreen and compiler told you that it isn’t aware about ConcreteScreen