作为对新编程语言的尝试，我构建了众所周知的数据结构，以熟悉语法和基本内容。出了语言。在这种情况下，我检查Objective-C中的堆栈。从Apple的使用对象，我们读到关键字'id'
...这是Objective-C中使用的一个特殊关键字，意思是“某种对象。”它是一个指向对象的指针，如（NSObject *），但它的特殊之处在于它不使用星号。
通过使用关键字“id”，似乎可以创建一个包含不同类型的Obj-C对象的堆栈数据结构;但是，我不确定这是否符合预期。为每种潜在的数据类型创建各种类方法是否更好，而不是尝试通用方法并确保每个堆栈遵循单个对象类型？这是我到目前为止所拥有的
XYZNode.h
#import <Foundation/Foundation.h>
@interface XYZNode : NSObject
@property id value;
@property XYZNode *next;
-(instancetype)initWithValue:(id)aValue next:(XYZNode *)aNext;
-(instancetype)init;
// Class factory methods should always start with the name of
// the class (without the prefix) that they create, with the
// exception of subclasses of classes with existing factory methods.
+(XYZNode *)nodeWithValue:(id)aValue nextNode:(XYZNode *)aNext;
@end
XYZNode.m
#import "XYZNode.h"
@implementation XYZNode
-(instancetype)initWithValue:(id)aValue next:(XYZNode *)aNext {
if (self = [super init]) {
_value = aValue;
_next = aNext;
} return self;
}
-(instancetype)init {
return [self initWithValue:nil next:nil];
}
+(XYZNode *)nodeWithValue:(id)aValue nextNode:(XYZNode *)aNext {
return [[self alloc] initWithValue:aValue next:aNext];
}
@end
XYZStack.h
#import <Foundation/Foundation.h>
@interface XYZStack : NSObject
-(void)pushValue:(id)aValue;
-(id)popValue;
-(BOOL)isEmpty;
-(instancetype)init;
-(instancetype)initWithValue:(id)aValue;
+(XYZStack *)stackWithValue:(id)aValue;
@end
XYZStack.m
#import "XYZStack.h"
#import "XYZNode.h"
// The extension hides how the values are stored
@interface XYZStack ()
@property XYZNode *lastNodeAdded;
@end
@implementation XYZStack
// Default initializer
-(instancetype)initWithValue:(id)aValue {
if (self = [super init]) {
_lastNodeAdded = nil;
}
if (aValue) {
[self pushValue:aValue];
}
return self;
}
// Call default initializer
-(instancetype)init{
return [self initWithValue:nil];
}
-(BOOL)isEmpty{
return ([self lastNodeAdded] == nil);
}
-(void)pushValue:(id)aValue {
[self setLastNodeAdded:[XYZNode nodeWithValue:aValue nextNode:[self lastNodeAdded]]];
}
-(id)popValue {
id temp = [[self lastNodeAdded] value];
[self setLastNodeAdded:[[self lastNodeAdded] next]];
return temp;
}
+(XYZStack *)stackWithValue:(id)aValue {
return [[self alloc] initWithValue:aValue];
}
@end
任何意见将不胜感激。