OC中类方法中仅仅为我们提供了一些降序方法,如今我们自定义方法,实现升序.
1.要求:定义一个Person类,实例变量包含name,age,height,定义几个对象,把这些对象保存在数组中,自定义方法,实现数组按name,age,gheight的升序排列输出.
首先Person.h文件
#import <Foundation/Foundation.h>
@interface Person : NSObject{
NSString *_name;//姓名
NSInteger _age;//年龄
CGFloat _height;//身高
}
//初始化
- (id)initWithName:(NSString *)name age:(NSInteger)age height:(CGFloat)height;
//姓名
- (void)setName:(NSString *)name;
- (NSString *)name;
//年龄
- (void)setAge:(NSInteger)age;
- (NSInteger)age;
//身高
- (void)setHeight:(CGFloat)height;
- (CGFloat)height;
//比較age
- (NSComparisonResult)compareByAge:(Person *)anPerson;
//比較身高
- (NSComparisonResult)compareByHeight:(Person *)anPerson;
//比較名字升序
- (NSComparisonResult)compareByName:(Person *)anPerson;
//名字降序
- (NSComparisonResult)compareByNameDesceding:(Person *)anPerson;
Person.m文件
#import "Person.h"
@implementation Person
#pragma mark - setter and getter
//set姓名
- (void)setName:(NSString *)name{
_name = name;
}
- (NSString *)name{
return _name;
}
//set年龄
- (void)setAge:(NSInteger)age{
_age = age;
}
- (NSInteger)age{
return _age;
}
//set身高
- (void)setHeight:(CGFloat)height{
_height = height;
}
- (CGFloat)height{
return _height;
}
#pragma mark - init method
//初始化
- (id)initWithName:(NSString *)name age:(NSInteger)age height:(CGFloat)height{
self = [super init];
if (self != nil) {
_name = name;
_age = age;
_height = height;
}
return self;
}
#pragma mark - override method
//重写description
- (NSString *)description{
return [NSString stringWithFormat:@"name:%@ age:%ld, height:%g", _name, _age, _height];
}
#pragma mark - compare
//比較年龄age
- (NSComparisonResult)compareByAge:(Person *)anPerson{
if ([self age] > [anPerson age]) {
return NSOrderedDescending;//1 降序
}else if([self age] == [anPerson age]){ //相等
return NSOrderedSame;//0
}else{
return NSOrderedAscending;//-1 升序
}
}
//比較身高
- (NSComparisonResult)compareByHeight:(Person *)anPerson{
if ([self height] > [anPerson height]) {
return NSOrderedDescending;
}else if([self height] == [anPerson height]){
return NSOrderedSame;
}else{
return NSOrderedAscending;
}
}
//比較名字
- (NSComparisonResult)compareByName:(Person *)anPerson{
return [[self name] compare:[anPerson name]];
}
//名字降序
- (NSComparisonResult)compareByNameDesceding:(Person *)anPerson{
return -[[self name] compare:[anPerson name]];
}
@end
主函数中main.m调用
#import <Foundation/Foundation.h>
#import "Person.h"
int main(int argc, const char * argv[])
{
@autoreleasepool {
Person *per1 = [[Person alloc] initWithName:@"xiaoshuai" age:12 height:178];
Person *per2 = [[Person alloc] initWithName:@"xiaomeng" age:22 height:175];
Person *per3 = [[Person alloc] initWithName:@"xiaoguangguang" age:20 height:180];
Person *per4 = [[Person alloc] initWithName:@"dapeng" age:30 height:190];
NSArray *perArr = [[NSArray alloc] initWithObjects:per1,per2,per3,per4, nil];
//对数组按姓名升序排序
NSArray *sortArrName = [perArr sortedArrayUsingSelector:@selector(compareByName:)];
NSLog(@"%@", sortArrName);
//对数组中年龄升序排序
NSArray *sortArrAge = [perArr sortedArrayUsingSelector:@selector(compareByAge:)];
NSLog(@"%@", sortArrAge);
//对数组中身高按升序排序
NSArray *sortArrHeight = [perArr sortedArrayUsingSelector:@selector(compareByHeight:)];
NSLog(@"%@", sortArrHeight);
//名字降序
NSArray *sortArrNameDescending = [perArr sortedArrayUsingSelector:@selector(compareByNameDesceding:)];
NSLog(@"%@", sortArrNameDescending);
}
return 0;
}測试结果:
2014-08-14 22:03:37.650 Lesson_Sort[4908:303] (
"name:dapeng age:30, height:190",
"name:xiaoguangguang age:20, height:180",
"name:xiaomeng age:22, height:175",
"name:xiaoshuai age:12, height:178"
)
2014-08-14 22:03:37.651 Lesson_Sort[4908:303] (
"name:xiaoshuai age:12, height:178",
"name:xiaoguangguang age:20, height:180",
"name:xiaomeng age:22, height:175",
"name:dapeng age:30, height:190"
)
2014-08-14 22:03:37.652 Lesson_Sort[4908:303] (
"name:xiaomeng age:22, height:175",
"name:xiaoshuai age:12, height:178",
"name:xiaoguangguang age:20, height:180",
"name:dapeng age:30, height:190"
)
2014-08-14 22:03:37.652 Lesson_Sort[4908:303] (
"name:xiaoshuai age:12, height:178",
"name:xiaomeng age:22, height:175",
"name:xiaoguangguang age:20, height:180",
"name:dapeng age:30, height:190"
)