Question

Something about inheritance, I have two class here: female, the subclass of human, and human, it can run but showing issues.

Two issues here:

main.m:29:10: ‘human’ may not respond to ‘setSexy:’

main.m:30:10: ‘human’ may not respond to ‘isSexy’

main.m

#import <Foundation/Foundation.h>
#import "female.h"

int main(int argc, const char * argv[])
{

    @autoreleasepool {

        human *sexyGirl = [[female alloc] init];

        [sexyGirl setName:@"SexyGirl"];
        [sexyGirl setGender:0];
        [sexyGirl setSexy:1];
        [sexyGirl isSexy];

    }
    return 0;
}

female.h

#import "human.h"

@interface female : human {
    BOOL sexy;
}

@property BOOL sexy;

-(void)isSexy;

@end

human.h

#import <Foundation/Foundation.h>

@interface human : NSObject {
    NSInteger *hp;
    NSString *name;
    BOOL gender;
}

@property (assign, nonatomic) NSInteger *hp;
@property (assign, nonatomic) NSString *name;
@property (assign, nonatomic) BOOL gender;

-(void) walk;

@end

Answer 1

There is no method name isSexy and setSexy in human class

You should change this human *sexyGirl = [[female alloc] init];

to this female *sexyGirl = [[female alloc] init];