單例，單例模式

單例，單例模式

#import <Foundation/Foundation.h>@interface Student : NSObject@property(retain,nonatomic)NSString *name;@property(assign,nonatomic)int age;//設計單利模式//+(類名＊)shareXXX//        defaultXXX//        xxx+(Student *)shareStudent;@end#import "Student.h"@implementation Student+(Student *)shareStudent{    //被static修飾的變數只會被初始化一次    static Student *stu=nil;    if (stu==nil) {        //如果學生對象為空白，就初始化學生對象        stu=[[Student alloc]init];    }    return stu;    }@end#import <Foundation/Foundation.h>#import "Student.h"int main(int argc, const char * argv[]){    @autoreleasepool {                //調用單例方法        //通過調用單例方法，返回的為同一個對象        //Student *stu=[Student shareStudent];是單例模式的建立對象的方法     Student *stu=[Student shareStudent];     stu.name=@"xiaowang";             Student *stu2=[Student shareStudent];     NSLog(@"%@", stu2.name);                                }    return 0;}