学生排序题

//  // 创建学生类 姓名 学号 年龄 成绩

// 创建五个学生对象,加入数组, 分别按姓名升序 学号降序 年龄升序 成绩降序排序

main.m

 1 #import <Foundation/Foundation.h>
 2 #import "Student.h"
 3 int main(int argc, const char * argv[]) {
 4     @autoreleasepool {
 5         // arc4random()%10  0---9
 6         //
 7         Student * s1 = [[Student alloc] initWithName:@"Jack" stuId:arc4random()%10+1 age:arc4random()%10+1 andScore:arc4random()%41 + 60];
 8         // 60 - 100
 9
10         Student * s2 = [[Student alloc] initWithName:@"Tom" stuId:arc4random()%10+1 age:arc4random()%10+1 andScore:arc4random()%41 + 60];
11
12         Student * s3 = [[Student alloc] initWithName:@"Lily" stuId:arc4random()%10+1 age:arc4random()%10+1 andScore:arc4random()%41 + 60];
13
14         Student * s4 = [[Student alloc] initWithName:@"Lucy" stuId:arc4random()%10+1 age:arc4random()%10+1 andScore:arc4random()%41 + 60];
15         Student * s5 = [[Student alloc] initWithName:@"Mark" stuId:arc4random()%10+1 age:arc4random()%10+1 andScore:arc4random()%41 + 60];
16
17 //        NSArray * arr = @[s1,s2,s3,s4,s5];
18         NSMutableArray * arr = [NSMutableArray array];
19         [arr addObject:s1];
20         [arr addObject:s2];
21         [arr addObject:s3];
22         [arr addObject:s4];
23         [arr addObject:s5];
24         // 成绩 降序
25         for (int i = 0; i< [arr count]; i++) {
26             for (int j = 0; j < [arr count] - i -1; j++) {
27                 Student * s1 = arr[j];
28                 Student * s2 = arr[j+1];
29                 if ([s1 isStuScoreLessThanAnother:s2]) {
30                     [arr exchangeObjectAtIndex:j withObjectAtIndex:j+1];
31                 }
32             }
33         }
34         NSLog(@"%@",arr);
35
36         NSArray * arr1 = [arr sortedArrayUsingSelector:@selector(isStuScoreLessThanAnother:)];
37         NSLog(@"%@",arr1);
38
39         // 年龄  左 < 右
40
41         NSArray * arr2 = [arr sortedArrayUsingComparator:^NSComparisonResult(Student * s1, Student * s2) {
42             return [s1 age] > [s2 age];
43         }];
44
45         NSLog(@"%@",arr2);
46
47
48         NSArray * arr3 = [arr sortedArrayUsingComparator:^NSComparisonResult(Student * obj1, Student * obj2) {
49             return [obj1 age] > [obj2 age];
50         }];
51         NSLog(@"%@",arr3);
52
53         NSArray * arr4 = [arr sortedArrayUsingComparator:^NSComparisonResult(Student * obj1, Student * obj2) {
54             return [obj1 score] < [obj2 score];
55         }];
56         NSLog(@"%@",arr4);
57
58
59     }
60     return 0;
61 }

main.m

 1 #import <Foundation/Foundation.h>
 2
 3 @interface Student : NSObject {
 4     NSString * _name;
 5     int _stuId;
 6     int _age;
 7     int _score;
 8 }
 9 - (id)initWithName:(NSString *)name stuId:(int)stuId age:(int)age andScore:(int)score;
10
11 - (int)score;
12 - (int)age;
13 - (BOOL)isStuScoreLessThanAnother:(Student *)s2;
14 @end

Student.h

 1 #import "Student.h"
 2
 3 @implementation Student
 4 - (id)initWithName:(NSString *)name stuId:(int)stuId age:(int)age andScore:(int)score {
 5     if (self = [super init]) {
 6         _name = name;
 7         _age = age;
 8         _stuId = stuId;
 9         _score = score;
10     }
11     return self;
12 }
13
14 - (int)score {
15     return _score;
16 }
17
18 - (NSString *)description {
19     return [NSString stringWithFormat:@"name:%@ stuId:%d age:%d score:%d",_name,_stuId,_age,_score];
20 }
21
22 - (int)age {
23     return _age;
24 }
25
26 - (BOOL)isStuScoreLessThanAnother:(Student *)s2 {
27     return [self score] < [s2 score];
28 }
29
30
31 @end

Student.m