Objective-c中+和-方法的区别

Objective-C是一种面向对象的编程语言，它支持两种类型的方法：实例方法和类方法。实例方法是通过实例对象进行调用的，而类方法则直接通过类名进行调用。在Objective-C中，类方法和实例方法的定义和调用方式有所不同。下面将详细介绍Objective-C中+和-方法的区别，并通过案例代码加以说明。

objective-c
@interface Person : NSObject
- (void)sayHello;
@end
@implementation Person
- (void)sayHello {
    NSLog(@"Hello, nice to meet you!");
}
@end

objective-c
Person *person = [[Person alloc] init];
[person sayHello];

objective-c
@interface Person : NSObject
+ (NSInteger)count;
@end
@implementation Person
static NSInteger count = 0;
+ (NSInteger)count {
    return count;
}
- (instancetype)init {
    self = [super init];
    if (self) {
        count++;
    }
    return self;
}
@end

objective-c
NSInteger numberOfPersons = [Person count];
NSLog(@"Number of persons: %ld", numberOfPersons);