数组排序

#pragma mark 冒泡排序
- (void)userArrSort:(NSMutableArray *)userArr
{
    int n = userArr.count;
    int i,j;
    NSDictionary *temp;
    for(j=0;j<n-1;j++)
    {
        for(i=0;i<n-1-j;i++)
        {
//            NSDictionary*ssy = [];
            if(((NSString *)[userArr[i] objectForKey:@"vlevel"]).intValue<((NSString *)[userArr[i+1] objectForKey:@"vlevel"]).intValue)//数组元素大小按升序排列
            {
                temp=userArr[i];
                userArr[i]=userArr[i+1];
                userArr[i+1]=temp;
            }
        }
    }
    for (int x = 0; x<userArr.count; x++)
    {
        if (1) {
//            [userArr replaceObjectAtIndex:0 withObject:[userArr[i]];
        }
    }
}
#pragma mark 已排序数组插入一条数据
- (void)insertObjectInUserArr:(NSMutableArray *)userArr withobject:(NSDictionary *)dic
{
    int j;
    if(((NSString *)[dic objectForKey:@"vlevel"]).intValue<=((NSString *)[userArr[userArr.count - 1] objectForKey:@"vlevel"]).intValue)
    {
        [userArr insertObject:dic atIndex:userArr.count];
    }else
    {
        for(int i=0;i<userArr.count;i++)
        {
            if(((NSString *)[dic objectForKey:@"vlevel"]).intValue>((NSString *)[userArr[i] objectForKey:@"vlevel"]).intValue)
            {
                j = i;
                [userArr insertObject:dic atIndex:j];
                break;
            }
        }
    }


}

（1）直接调用系统的方法排序int

NSMutableArray*array = [[NSMutableArrayalloc]init];

[arrayaddObject:[NSNumbernumberWithInt:20]];

[arrayaddObject:[NSNumbernumberWithInt:1]];

[arrayaddObject:[NSNumbernumberWithInt:4]];

NSArray*sortedArray = [arraysortedArrayUsingSelector:@selector(compare:)];

for(inti =0; i < [sortedArraycount]; i++)

{

intx = [[sortedArrayobjectAtIndex:i]intValue];

NSLog(@"######%d ", x);

}

 

（2）用descriptor方法

#import<Cocoa/Cocoa.h>

@interfaceNode: NSObject {

intx;

inty;

intv;

}

@property intx;

@property inty;

@property intv;

- (id)init:(int)tx y:(int)ty v:(int)tv;

@end

@implementationNode

@synthesizex;

@synthesizey;

@synthesizev;

- (id)init:(int)tx y:(int)ty v:(int)tv {

x= tx;

y= ty;

v= tv;

return self;

}

@end

intmain(intargc,char*argv[])

{

NSMutableArray *myMutableArray = [[NSMutableArrayalloc]init];

Node *n[2];

n[0] = [[Nodealloc]init:2y:1v:1];

n[1] = [[Nodealloc]init:4y:2v:2];

[myMutableArrayaddObject:n[0]];

[myMutableArrayaddObject:n[1]];

NSSortDescriptor* sortByA = [NSSortDescriptorsortDescriptorWithKey:@"x"ascending:NO];

[myMutableArraysortUsingDescriptors:[NSArrayarrayWithObject:sortByA]];

for(Node*tinmyMutableArray) {

NSLog(@"x === %d", t.x);

NSLog(@"y === %d", t.y);

NSLog(@"v === %d", t.v);

}

}

（3）自定义重写方法

/*

Abstract:Constants returned by comparison functions, indicating whether a value is equal to, less than, or greater than another value.

Declaration:enumCFComparisonResult{

kCFCompareLessThan= -1,

kCFCompareEqualTo= 0,

kCFCompareGreaterThan= 1

};

*/

#import<Cocoa/Cocoa.h>

@implementation NSNumber (MySort)

- (NSComparisonResult) myCompare:(NSString *)other {

//这里可以作适当的修正后再比较

int result = ([selfintValue]>>1) - ([other intValue]>>1);

//这里可以控制排序的顺序和逆序

return result < 0 ?NSOrderedDescending : result >0 ?NSOrderedAscending :NSOrderedSame;

}

@end

int main(int argc, char *argv[])

{

NSMutableArray *array = [[NSMutableArrayalloc]init];

[arrayaddObject:[NSNumbernumberWithInt:20]];

[arrayaddObject:[NSNumbernumberWithInt:1]];

[arrayaddObject:[NSNumbernumberWithInt:4]];

NSArray *sortedArray = [arraysortedArrayUsingSelector:@selector(myCompare:)];

for(int i = 0; i < [sortedArraycount]; i++)

{

int x = [[sortedArrayobjectAtIndex:i]intValue];

NSLog(@"######%d ", x);

}

}

c语言实现的学生成绩管理系统是面向过程的,而OC实现的学生成绩管理系统则是面向对象的.

对该系统的重难点讲述如下:

1.排序.系统中的四个关键字分别是 stuID,姓名,年龄,成绩.我们可以选择这四种方式并选择 升降序的方法进行排序.

系统中使用的是  NSmutableArray 存储数据.那么如何对对象是类成员的数组排序呢?

先看看NSMutableArray排序的几种方式.

1)使用@Seletor选择器调用方法排序.

NSMutableArray *array = [[NSMutableArray alloc]init];
    [array addObject:[NSNumber numberWithInt:10]];
    [array addObject:[NSNumber numberWithInt:20]];
    [array addObject:[NSNumber numberWithInt:0]];
    [array addObject:[NSNumber numberWithInt:1]];
    [array addObject:[NSNumber numberWithInt:3]];
    NSLog(@"未排序的数组:%@",array);

    NSArray *sortedArray = [array sortedArrayUsingSelector:@selector(compare:)];
     NSLog(@"yi排序的数组:%@",sortedArray);
    /*
     2013-11-29 08:28:00.616 OC实现学生成绩管理系统[451:303] 未排序的数组:(
     10,
     20,
     0,
     1,
     3
     )
     2013-11-29 08:28:00.621 OC实现学生成绩管理系统[451:303] yi排序的数组:(
     0,
     1,
     3,
     10,
     20
     )
     */

同时也适用于类对象.

//直接实现静态方法，获取带有name和age的Person对象
+(Person *)personWithAge:(int) age withName:(NSString *)name{
    Person *person = [[Person alloc] init];
    person.age = age;
    person.name = name;
    return person;
}

//自定义排序方法
-(NSComparisonResult)comparePerson:(Person *)person{
  //默认按年龄排序
    NSComparisonResult result = [[NSNumber numberWithInt:person.age] compare:[NSNumber numberWithInt:self.age]];//注意:基本数据类型要进行数据转换
  //如果年龄一样，就按照名字排序
    if (result == NSOrderedSame) {
        result = [self.name compare:person.name];
    }
    return result;
}

2.高级排序,使用排序描述器:使用descriptor方法对Array中成员是类对象的类型进行按@propery 列进行排序.

  

-(void)SortStudentArray//
{
    NSLog(@"按照学号排序请输入 (id)");

    NSLog(@"按姓名排序请输入(name)");

    NSLog(@"按照年龄排序请输入(age)");

    NSLog(@"按照成绩排序(score)请输入:");

    char charKey[10] ;
    scanf("%s",charKey);

    NSString *tempkey = [NSString stringWithUTF8String:charKey];
    NSString *key = [tempkey lowercaseString];
      BOOL ascending = NO;
    NSLog(@"是否开启降序模式( 默认不开启 )?(yes or no):");
    char ascendingStr[10] ;
    scanf("%s",ascendingStr);
    NSString *ascendingKey =[[NSString stringWithUTF8String:ascendingStr] lowercaseString];

    if ([ascendingKey isEqualToString:@"yes"])
        ascending = YES;
    else
        ascending = NO;


    if ([key isEqualToString:@"id"]) {

        NSSortDescriptor *sortByID = [NSSortDescriptor sortDescriptorWithKey:@"stuID" ascending:ascending];
       // 建立NSSortDescriptor 对象,按照的属性列,是否是asc升序?

        [studentArray sortUsingDescriptors:[NSArray arrayWithObject:sortByID]];
        //按照建立的descriptor进行排序.
    }
    else if([key isEqualToString:@"name"])
    {
        NSSortDescriptor *sortByName= [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:ascending];

        [studentArray sortUsingDescriptors:[NSArray arrayWithObject:sortByName]];


    }
    else if([ key isEqualToString:@"age"])
    {
        NSSortDescriptor *sortByAge = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:ascending];

        [studentArray sortUsingDescriptors:[NSArray arrayWithObject:sortByAge]];


    }
    else if ([key isEqualToString:@"score"])
    {
        NSSortDescriptor *sortByScore = [NSSortDescriptor sortDescriptorWithKey:@"score" ascending:ascending];

        [studentArray sortUsingDescriptors:[NSArray arrayWithObject:sortByScore]];


    }


}

上述代码就是我在管理系统中实现的,结果将在系统中呈现.

3.自定义重写方法进行排序.使用Block进行排序.

NSArray *array = [NSArray arrayWithObjects:@"1bc",@"4b6",@"123",@"789",@"3ef", nil nil];
       NSArray *sortedArray = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {

           //这里的代码可以参照上面compare:默认的排序方法，也可以把自定义的方法写在这里，给对象排序
           NSComparisonResult result = [obj1 compare:obj2];
           return result;
       }];
       NSLog(@"排序后:%@",sortedArray);

2013-11-29 08:42:56.723 OC实现学生成绩管理系统[483:303] 排序后:(

    123,

    1bc,

    3ef,

    4b6,

    789

)