7、block、数组排序2

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7、block、数组排序2

Student.h

#import <Foundation/Foundation.h>@interface Student : NSObject{    NSInteger _num;    NSString *_name;    NSInteger _age;    CGFloat _score;}- (void)setNum:(NSInteger)num;- (NSInteger)num;- (void)setName:(NSString *)name;- (NSString *)name;- (void)setAge:(NSInteger)age;- (NSInteger)age;- (void)setScore:(CGFloat)score;- (CGFloat)score;- (instancetype)initWithNum:(NSInteger)num                       name:(NSString *)name                        age:(NSInteger)age                      score:(CGFloat)score;+ (instancetype)studentWithNum:(NSInteger)num                          name:(NSString *)name                           age:(NSInteger)age                         score:(CGFloat)score;@end

Student.m

#import "Student.h"@implementation Student- (void)setNum:(NSInteger)num{    _num = num;}- (NSInteger)num{    return _num;}- (void)setName:(NSString *)name;{    _name = name;}- (NSString *)name{    return _name;}- (void)setAge:(NSInteger)age{    _age = age;}- (NSInteger)age{    return _age;}- (void)setScore:(CGFloat)score{    _score = score;}- (CGFloat)score{    return _score;}- (instancetype)initWithNum:(NSInteger)num                       name:(NSString *)name                        age:(NSInteger)age                      score:(CGFloat)score{    self = [super init];    if (self) {        _num = num;        _name = name;        _age = age;        _score = score;    }    return self;}+ (instancetype)studentWithNum:(NSInteger)num                          name:(NSString *)name                           age:(NSInteger)age                         score:(CGFloat)score{    return [[Student alloc] initWithNum:num name:name age:age score:score];}- (NSString *)description{    return [NSString stringWithFormat:@"num = %ld, name = %@, age = %ld, score = %.2f", _num, _name, _age, _score];}@end

main.m

#import <Foundation/Foundation.h>#import "Student.h"// 给block起别名typedef CGFloat (^CalBlock) (CGFloat, CGFloat);int main(int argc, const char * argv[]) {    @autoreleasepool {        // eg.1 写⼀个 返回值为整型 参数为NSString(仅一个参数)的block,实现将字符串转换为整型的功能。        int (^block1) (NSString *str) = ^int (NSString *str) {            return [str intValue];        };        // 简写        int (^block2) (NSString *) = ^(NSString *str) {            NSLog(@"block内部");            return [str intValue];        };        // 类型：int (^) (NSString *)        // 变量名：block1        NSLog(@"block外部");        // 回调        // 调用block实现将字符串转换为数字        int i = block2(@"1234");        NSLog(@"%d", i);        // 声明block变量，将浮点型数字变为字符串        NSString * (^block3) (float) = ^(float f) {            return [NSString stringWithFormat:@"%.2f", f];        };        NSString *str = block3(8188.8);        NSLog(@"str = %@", str);        // 实现两个NSInteger的和、差、积、商        // 和        NSInteger (^block4) (NSInteger, NSInteger) = ^(NSInteger a, NSInteger b) {            return a + b;        };        NSInteger sum = block4(10, 20);        NSLog(@"sum = %ld", sum);        // 差        NSInteger (^block5) (NSInteger, NSInteger) = ^(NSInteger a, NSInteger b) {            return a - b;        };        NSInteger sub = block5(10, 29);        NSLog(@"sub = %ld", sub);        // 积        NSInteger (^block6) (NSInteger, NSInteger) = ^(NSInteger a, NSInteger b) {            return a * b;        };        NSInteger mul = block6(10, 3);        NSLog(@"mul = %ld", mul);        // 商        CGFloat (^block7) (CGFloat, CGFloat) = ^(CGFloat a, CGFloat b) {            return a / b;        };        CGFloat div = block7(34.9, 12.0);        NSLog(@"div = %.2f", div);        // 判断数组中是否存在某个元素        BOOL (^block0) (NSArray *, NSString *) = ^(NSArray *arr, NSString *str) {            return [arr containsObject:str];        };        BOOL b = block0(@[@"aab", @"bb", @"cc"], @"bb");        NSLog(@"b = %d", b);        // 使用新类型定义block变量        __block int bei = 10;        CalBlock productBlock = ^(CGFloat f1, CGFloat f2) {            bei = 100;            return f1 * f2 * bei;        };        CGFloat product = productBlock(1.2, 3.0);        NSLog(@"%.2f", product);        // block内部可使用外部局部变量的值，但不能修改，若要修改，需用 __block 修饰变量        // block可使用和修改全局变量的值        // 使用block对数组排序        NSArray *namesArray = @[@"hehe", @"xx", @"jian", @"daozhang", @"qing"];////        NSComparisonResult (^sortBlock) (id, id) = ^(id obj1, id obj2) {//            // or return [obj1 compare:obj2];//            if ([obj1 compare:obj2] == NSOrderedDescending) {//                return -1L;//            } else {//                return 1L;//            }//        };//        namesArray = [namesArray sortedArrayUsingComparator:sortBlock];//        NSLog(@"%@", namesArray);        namesArray = [namesArray sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {            if ([obj1 compare:obj2] == NSOrderedDescending) {                return 1l;            }            return 0l;        }];        NSLog(@"%@", namesArray);        // 可变数组排序，排序方法没有返回值        NSMutableArray *numbersArray = [NSMutableArray arrayWithObjects:@"123", @"345", @"234", @"56", @"2356", nil];        [numbersArray sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {            int a = [obj1 intValue];    // 按整型数字排序            int b = [obj2 intValue];            if (a < b) {                return 1L;            }            return 0L;        }];        NSLog(@"%@", numbersArray);        // 创建学生对象        Student *stu1 = [[Student alloc] initWithNum:1002 name:@"laoda" age:18 score:78.9];        Student *stu2 = [[Student alloc] initWithNum:1005 name:@"laoer" age:19 score:78.9];        Student *stu3 = [[Student alloc] initWithNum:1001 name:@"laosan" age:20 score:78.9];        Student *stu4 = [[Student alloc] initWithNum:1004 name:@"laosi" age:17 score:78.9];        Student *stu5 = [[Student alloc] initWithNum:1003 name:@"laowu" age:21 score:87.0];        NSMutableArray *studentArray = [NSMutableArray arrayWithObjects:stu1, stu2, stu3, stu4, stu5, nil];        [studentArray sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {//            Student *s1 = obj1;//            Student *s2 = obj2;//            if (s1.age < s2.age) {//                return 1L;//            }//            return 0L;            // or            if ([obj1 age] < [obj2 age]) {                return 1L;            }            return 0L;        }];        NSLog(@"%@", studentArray);    }    return 0;}

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