I'm getting Failed with exit code 1 error in xcode

This is my first ever attempt at a Objective-c cocoa program, so I have no clue why it is giving me that error. I really don't understand the Build Result page either.

myClass.h

#import <Cocoa/Cocoa.h>


@interface myClass : NSObject {
    int a;
    int b;
}

-(void) setvara:(int)x;
-(void) setvarb:(int)y;
-(int) add;

@end

myClass.m

#import "myClass.h"


@implementation myClass

-(void)setvara:(int)x{
    a=x;    
}

-(void)setvarb:(int)y{
    b=y;    
}

-(int)add{
    return a+b; 
}
@end

main.m

#import <Cocoa/Cocoa.h>
#import <stdio.h>
#import "myClass.m"

int main(int argc, const char* argv[])
{
    myClass* class = [[myClass alloc]init];

    [class setvara:5];
    [class setvarb:6];

    printf("The sum: %d", [class add]);

    [class release];

}