Java 接口和 Objective-C 协议之间的区别

Java 接口和 Objective-C 协议是两种不同编程语言中用于定义一组方法的机制。在本文中，我们将讨论它们之间的区别，并提供一些示例代码来说明这些区别。

java
public interface Printable {
    void print();
    void scan();
}

objective-c
@protocol Printable
- (void)print;
@optional
- (void)scan;
@end

java
public interface Printable {
    void print();
    void scan();
}
public class Printer implements Printable {
    @Override
    public void print() {
        System.out.println("Printing...");
    }
    
    @Override
    public void scan() {
        System.out.println("Scanning...");
    }
}
public class Main {
    public static void main(String[] args) {
        Printable printer = new Printer();
        printer.print();
        printer.scan();
    }
}

objective-c
@protocol Printable
- (void)print;
@optional
- (void)scan;
@end
@interface Printer : NSObject 
@end
@implementation Printer
- (void)print {
    NSLog(@"Printing...");
}
- (void)scan {
    NSLog(@"Scanning...");
}
@end
int main() {
    id printer = [[Printer alloc] init];
    [printer print];
    [printer scan];
    
    return 0;
}