你遗忘的都在这里—iOS常用类型方法笔记

时间：2023-03-09 23:56:29
你遗忘的都在这里—iOS常用类型方法笔记

　　这些都是项目中常用但又常忘的方法，与大家分享一下。

一、NSString

创建字符串。 

 NSString *astring = @"This is a String!";

创建空字符串，给予赋值。 

 NSString *astring = [[NSString alloc] init];  

 astring = @"This is a String!";  

 NSLog(@"astring:%@",astring);

使用变量初始化 

    NSString *name = @"Ivan!";

    NSString *astring = [[NSString stringWithFormat:@”My name is %@!”,name]];

    NSLog(@"astring:%@",astring);

判断是否包含某字符串 

检查字符串是否以另一个字符串开头

      - (BOOL) hasPrefix: (NSString *) aString;

      NSString *String1 = @"NSStringInformation.txt";

      [String1 hasPrefix:@"NSString"] ==  ?  NSLog(@"YES") : NSLog(@"NO");

      [String1 hasSuffix:@".txt"] ==  ?  NSLog(@"YES") : NSLog(@"NO");

是否包含其它字符 

     NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];

     Boolean contains = [astring rangeOfString:@”This”].length>;

从文件读取字符串:

      initWithContentsOfFile方法

      NSString *path = @"astring.text";

      NSString *astring = [[NSString alloc] initWithContentsOfFile:path];

      NSLog(@"astring:%@",astring);

写字符串到文件:writeToFile方法  

      NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];

      NSLog(@"astring:%@",astring);

      NSString *path = @"astring.text";

      [astring writeToFile: path atomically: YES];

比较两个字符串      

isEqualToString方法     

      NSString *astring01 = @"This is a String!";

      NSString *astring02 = @"This is a String!";

      BOOL result = [astring01 isEqualToString:astring02];

      NSLog(@"result:%d",result);

compare方法(comparer返回的三种值)

      NSString *astring01 = @"This is a String!";

      NSString *astring02 = @"This is a String!";

      BOOL result = [astring01 compare:astring02] = = NSOrderedSame;

      NSLog(@"result:%d",result);

NSOrderedSame判断两者内容是否相同

      NSString *astring01 = @"This is a String!";

      NSString *astring02 = @"this is a String!";

      BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;

      NSLog(@"result:%d",result);

不考虑大小写比较字符串1 

     NSString *astring01 = @"this is a String!";

     NSString *astring02 = @"This is a String!";

     BOOL result = [astring01 caseInsensitiveCompare:astring02] = = NSOrderedSame;

     NSLog(@"result:%d",result);

改变字符串的大小写  

     NSString *string1 = @"A String";

     NSString *string2 = @"String";

     NSLog(@"string1:%@",[string1 uppercaseString]);//大写

     NSLog(@"string2:%@",[string2 lowercaseString]);//小写

     NSLog(@"string2:%@",[string2 capitalizedString]);//首字母大小

在串中搜索子串      

     NSString *string1 = @"This is a string";

     NSString *string2 = @"string";

     NSRange range = [string1 rangeOfString:string2];

     int location = range.location;

     int leight = range.length;

     NSString *astring = [[NSString alloc] initWithString:[NSString    stringWithFormat:@"Location:%i,Leight:%i",location,leight]];

     NSLog(@"astring:%@",astring);

替换字符串 

     NSString *astring01 = @"hello 中国";

     NSString * new = [astring01 stringByReplacingOccurrencesOfString:@”中国” withString:@"北京"];

     NSLog(new);

分割字符串成数组 

     NSString *s = @"a b d e f";

     NSArray *arr = [s componentsSeparatedByString:@" "];

     NSLog(@"count = %d",[arr count]);

字符串数组拼接成字符串 

      NSArray *pathArray = [NSArray arrayWithObjects:@"here", @"be", @"dragons", nil];

      NSLog(@"%@",[pathArray componentsJoinedByString:@""]);

抽取子串      

     //substringToIndex: 从字符串的开头一直截取到指定的位置，但不包括该位置的字符

     NSString *string1 = @"This is a string";

     NSString *string2 = [string1 substringToIndex:];

     NSLog(@"string2:%@",string2); 
     //-substringFromIndex: 以指定位置开始（包括指定位置的字符），并包括之后的全部字符

     NSString *string1 = @"This is a string";

     NSString *string2 = [string1 substringFromIndex:];

     NSLog(@"string2:%@",string2);  
     //substringWithRange: //按照所给出的位置，长度，任意地从字符串中截取子串

     NSString *string1 = @"This is a string";

     NSString *string2 = [string1 substringWithRange:NSMakeRange(, )];

     NSLog(@"string2:%@",string2);

二、NSMutableString

给字符串分配容量

     //stringWithCapacity:

     NSMutableString *String;

     String = [NSMutableString stringWithCapacity:];

在已有字符串后面添加字符

     //appendString: and appendFormat:

     NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];

     //[String1 appendString:@", I will be adding some character"];

     [String1 appendFormat:[NSString stringWithFormat:@", I will be adding some character"]];

     NSLog(@"String1:%@",String1);

在已有字符串中按照所给出范围和长度删除字符

     //deleteCharactersInRange:

     NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];

     [String1 deleteCharactersInRange:NSMakeRange(, )];

     NSLog(@"String1:%@",String1);

在已有字符串后面在所指定的位置中插入给出的字符串

     //-insertString: atIndex:

     NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];

     [String1 insertString:@"Hi! " atIndex:];

     NSLog(@"String1:%@",String1);

将已有的换成其它的字符串

     //-setString:

     NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];

     [String1 setString:@"Hello Word!"];

     NSLog(@"String1:%@",String1);

按照所给出的范围，和字符串替换的原有的字符

     //-setString:

     NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];

     [String1 replaceCharactersInRange:NSMakeRange(, ) withString:@"That"];

     NSLog(@"String1:%@",String1);

三、NSArray

创建数组

     NSArray *array = [[NSArray alloc] initWithObjects: @"One",@"Two",@"Three",@"Four",nil];

     self.dataArray = array;

     //- (unsigned) Count;数组所包含对象个数；

     NSLog(@"self.dataArray cound:%d",[self.dataArray count]);

     //获取指定索引处的对象

     NSLog(@"self.dataArray cound 2:%@",[self.dataArray objectAtIndex:]);

从一个数组拷贝数据到另一数组

     //arrayWithArray:

      //NSArray *array1 = [[NSArray alloc] init];

      NSMutableArray *MutableArray = [[NSMutableArray alloc] init];

      NSArray *array = [NSArray arrayWithObjects: @"a",@"b",@"c",nil];

      NSLog(@"array:%@",array);

      MutableArray = [NSMutableArray arrayWithArray:array];

      NSLog(@"MutableArray:%@",MutableArray);

      array1 = [NSArray arrayWithArray:array];

      NSLog(@"array1:%@",array1);

      //Copy

      //id obj;

      NSMutableArray *newArray = [[NSMutableArray alloc] init];

      NSArray *oldArray = [NSArray arrayWithObjects: @"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];

      NSLog(@"oldArray:%@",oldArray);

      for(int i = ; i < [oldArray count]; i++)

      {

          obj = [[oldArray objectAtIndex:i] copy];

          [newArray addObject: obj];

      }

      //

      NSLog(@"newArray:%@", newArray);

快速遍历数组

      //NSMutableArray *newArray = [[NSMutableArray alloc] init];

      NSArray *oldArray = [NSArray arrayWithObjects: @"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];

      NSLog(@"oldArray:%@",oldArray);

      for(id obj in oldArray)

      {

          [newArray addObject: obj];

      }

      //

      NSLog(@"newArray:%@", newArray);

      [newArray release];

  Copy and sort

      //NSMutableArray *newArray = [[NSMutableArray alloc] init];

      NSArray *oldArray = [NSArray arrayWithObjects: @"b",@"a",@"e",@"d",@"c",@"f",@"h",@"g",nil];

      NSLog(@"oldArray:%@",oldArray);

      NSEnumerator *enumerator;

      enumerator = [oldArray objectEnumerator];

      id obj;

      while(obj = [enumerator nextObject])

      {

          [newArray addObject: obj];

      }

      [newArray sortUsingSelector:@selector(compare:)];

      NSLog(@"newArray:%@", newArray);

给数组分配容量

     NSArray *array;

     array = [NSMutableArray arrayWithCapacity:];

在数组末尾添加对象

      //- (void) addObject: (id) anObject;

     NSMutableArray *array = [NSMutableArray arrayWithObjects:@"One",@"Two",@"Three",nil];

     [array addObject:@"Four"];

     NSLog(@"array:%@",array);

删除数组中指定索引处对象

     //-(void) removeObjectAtIndex: (unsigned) index;

     NSMutableArray *array = [NSMutableArray arrayWithObjects:@"One",@"Two",@"Three",nil];

     [array removeObjectAtIndex:];

     NSLog(@"array:%@",array);

数组枚举

从前向后

     NSMutableArray *array = [NSMutableArray arrayWithObjects: @"One",@"Two",@"Three",nil];

     NSEnumerator *enumerator;

     enumerator = [array objectEnumerator];

     id thingie;

     while (thingie = [enumerator nextObject]) {

     NSLog(@"thingie:%@",thingie);

     }

从后向前

     NSMutableArray *array = [NSMutableArray arrayWithObjects: @"One",@"Two",@"Three",nil];

     NSEnumerator *enumerator;

     enumerator = [array reverseObjectEnumerator];

     id object;

     while (object = [enumerator nextObject]) {

         NSLog(@"object:%@",object);

     }

快速枚举

     //NSMutableArray *array = [NSMutableArray arrayWithObjects:  @"One",@"Two",@"Three",nil];

     for(NSString *string in array)

     {

         NSLog(@"string:%@",string);

     }

创建字典

     //- (id) initWithObjectsAndKeys;

     ctionary *dictionary = [[NSDictionary alloc]   initWithObjectsAndKeys:@"One",@"",@"Two",@"",@"Three",@"",nil];

     NSString *string = [dictionary objectForKey:@"One"];

     NSLog(@"string:%@",string);

     NSLog(@"dictionary:%@",dictionary);

NSMutableDictionary 

 //创建

 NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];

 //添加字典

 [dictionary setObject:@"One" forKey:@""];

 [dictionary setObject:@"Two" forKey:@""];

 [dictionary setObject:@"Three" forKey:@""];

 [dictionary setObject:@"Four" forKey:@""];

 NSLog(@"dictionary:%@",dictionary);

 //删除指定的字典

 [dictionary removeObjectForKey:@""];

 NSLog(@"dictionary:%@",dictionary);

NSValue（对任何对象进行包装）

将NSRect放入NSArray中

     NSMutableArray *array = [[NSMutableArray alloc] init];

     NSValue *value;

     CGRect rect = CGRectMake(, , , );

     value = [NSValue valueWithBytes:&rect objCType:@encode(CGRect)];

     [array addObject:value];

     NSLog(@"array:%@",array);

从Array中提取

     value = [array objectAtIndex:];

     [value getValue:&rect];

     NSLog(@"value:%@",value);

定义结构体并添加到NSArray里面

     typedef struct {

     float real;

     float imaginary;

     } ImaginaryNumber;

     ImaginaryNumber miNumber;

     miNumber.real = 1.1;

     miNumber.imaginary = 1.41;

     NSValue *miValue = [NSValue value:miNumber  withObjCType:@encode(ImaginaryNumber)]; // encode using the type name

     ImaginaryNumber miNumber2;

     [miValue getValue:&miNumber2];

四、宏定义#define讲解

NSNumber 

 + (NSNumber *)numberWithInt:(int)value;

 + (NSNumber *)numberWithDouble:(double)value;

 - (int)intValue;

 - (double)doubleValue;

NSNumber可以将基本数据类型包装起来，形成一个对象，这样就可以给其发送消息，装入NSArray中等等。

     NSNumber * intNumber=[NSNumber numberWithInt：]；

     NSNumber *floatNumber=[NSNUmber numberWithFloat:100.00];

     int i=[intNumber intValue]；

     if([intNumber isEqualToNumber:floatNumber]) ....

NSNumber继承NSObject ，可以使用比较 compare： isEqual等消息

NSNull

IOS里面最小简单的类，里面只有一个方法+(NSNull*) null;

数学常用方法

数学常量：

 #define M_E         2.71828182845904523536028747135266250   // e

 #define M_LOG2E     1.44269504088896340735992468100189214   // log 2e

 #define M_LOG10E    0.434294481903251827651128918916605082  // log 10e

 #define M_LN2       0.693147180559945309417232121458176568  // log e2

 #define M_LN10      2.30258509299404568401799145468436421   // log e10

 #define M_PI        3.14159265358979323846264338327950288   // pi

 #define M_PI_2      1.57079632679489661923132169163975144   // pi/2

 #define M_PI_4      0.785398163397448309615660845819875721  // pi/4

 #define M_1_PI      0.318309886183790671537767526745028724  // 1/pi

 #define M_2_PI      0.636619772367581343075535053490057448  // 2/pi

 #define M_2_SQRTPI  1.12837916709551257389615890312154517   // 2/sqrt(pi)

 #define M_SQRT2     1.41421356237309504880168872420969808   // sqrt(2)

 #define M_SQRT1_2   0.707106781186547524400844362104849039  // 1/sqrt(2)

常用函数：

指数运算

 NSLog(@"%.f", pow(,) ); //result 9

 NSLog(@"%.f", pow(,) ); //result 27

开平方运算（计算两点间的距离时用到）

 NSLog(@"%.f", sqrt() ); //result 4

 NSLog(@"%.f", sqrt() ); //result 9

上舍入

 NSLog(@"res: %.f", ceil(3.000000000001)); //result 4

 NSLog(@"res: %.f", ceil(3.00)); //result 3

下舍入

 NSLog(@"res: %.f", floor(3.000000000001)); //result 3

 NSLog(@"res: %.f", floor(3.9999999)); //result 3

四舍五入

 NSLog(@"res: %.f", round(3.5)); //result 4

 NSLog(@"res: %.f", round(3.46)); //result 3

 NSLog(@"res: %.f", round(-3.5)); //NB: this one returns -4  

最小值

 NSLog(@"res: %.f", fmin(,)); //result 5  

最大值

 NSLog(@"res: %.f", fmax(,)); //result 10

绝对值

 NSLog(@"res: %.f", fabs()); //result 10

 NSLog(@"res: %.f", fabs(-)); //result 10

NSDate

得到当前的日期

NSDate *date = [NSDate date];

日期之间比较可用以下方法

 - (BOOL)isEqualToDate:(NSDate *)otherDate;// 与otherDate比较，相同返回YES

 - (NSDate *)earlierDate:(NSDate *)anotherDate;// 与anotherDate比较，返回较早的那个日期

 - (NSDate *)laterDate:(NSDate *)anotherDate;//与anotherDate比较，返回较晚的那个日期

将日期转换成字符串

 NSLog(@”date = %@”,[data description]);

设置日期显示格式

  NSDateFormatter *formatter =[[[NSDateFormatter alloc] init] autorelease];

  [formatter setTimeStyle:NSDateFormatterFullStyle]; //设置几种默认的显示效果

  [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss a"];//设置自定义的显示效果

  NSLog([formatter stringFromDate:date]);

NSData

//NSData－> NSString

NSString *aString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

//NSString－>NSData

NSString *aString = @"1234abcd";

NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];

NSString和Time

 // 创建字符串

 - (void)CreatString

 {

     // <1> 创建字符创

     NSString *strS = @"This is a String!";

     // <2> 创建空字符串,给予赋值

     NSString *strK = [[NSString alloc] init];

     strK = @"This is a String!";

     NSLog(@"strS:%@, strK%@",strS,strK);

     // <3> 使用变量初始化字符串

     NSString *name = @"aofe";

     NSString *strN = [NSString stringWithFormat:@"My name is %@",name];

     NSLog(@"strN:%@",strN);

 }

 // 判断是否包含某字符串

 - (void)IsContainsString

 {

     NSString *str1 = @"NSStringInformation.txt";

     // <1> 检查字符串是否以另一个字符串开头

     [str1 hasPrefix:@"NSString"] == ? NSLog(@"YES") :NSLog(@"NO");

     // <2> 检查字符串是否以另一个字符串结尾

     [str1 hasSuffix:@".txt"] == ? NSLog(@"YES") :NSLog(@"NO");

     // <3> 检查字符串是否包含其他字符串

     [str1 rangeOfString:@"Information"].length >  ? NSLog(@"YES") :NSLog(@"NO");

 }

 // 读写字符串

 -(void)WriteAndReadString

 {

     // 文件路径

     NSString *path = @"wenJianQuanLuJing";

     // <1> 从文件读取字符串

     NSString *strW = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:NULL];

     // <2> 将字符串写入到文件

     [strW writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:NULL];

 }

 // 比较两个字符串

 -(void)ComparerTwoString

 {

     NSString *str1 = @"This is String1";

     NSString *str2 = @"THIS is String2";

     // 比较两个字符串是否相等

     BOOL result1 = [str1 isEqualToString:str2];

     // 比较两个字符串(comparer方法返回三种值:NSOrderedAscending = -1L, NSOrderedSame, NSOrderedDescending)

     NSComparisonResult result2 = [str1 compare:str2];

     // 不考虑大小比较字符串

     NSComparisonResult result3 = [str1 caseInsensitiveCompare:str2];

     NSLog(@"result1:%d,result2:%ld,result3:%ld",result1,(long)result2,(long)result3);

 }

 // 改变字符串的大小写

 -(void)ChangeStringCase

 {

     NSString *str1 = @"this is string1";

     NSString *str2 = @"THIS IS STRING2";

     // 全部大写

     [str1 uppercaseString];

     // 全部小写

     [str2 lowercaseString];

     // 首字母大写

     [str1 capitalizedString];

 }

 // 在字符串中搜索子串

 -(void)SearchString

 {

     NSString *str1 = @"This is String1";

     NSString *str2 = @"is";

     NSRange range = [str1 rangeOfString:str2];

     NSLog(@"location:%lu,length:%lu",(unsigned long)range.location,(unsigned long)

           range.length);

 }

 // 替换字符串

 -(void)ReplaceString

 {

     NSString *strL = @"hello china";

     NSString *strN = [strL stringByReplacingOccurrencesOfString:@"china" withString:@"beijing"];

     NSLog(@"strL:%@,strN:%@",strL,strN);

 }

 // 分隔字符串成数组

 -(void)ComponentsString

 {

     NSString *str = @"a b c d e";

     // 以空格分隔字符串成数组

     NSArray *arr = [str componentsSeparatedByString:@" "];

     NSLog(@"arr:%@,arr.count:%lu",arr,(unsigned long)arr.count);

 }

 // 数组拼接成字符串

 -(void)ArrayToString

 {

     NSArray *array = [NSArray arrayWithObjects:@"this",@"is",@"String", nil];

     // 用空格隔开数组中的元素

     NSString *str = [array componentsJoinedByString:@" "];

     NSLog(@"str:%@",str);

 }

 // 从字符串中抽取出新的字符串

 -(void)DrawNewString

 {

     NSString *str = @"This is String";

     // 从字符串的开头一直截取到指定位置,但不包括该位置的字符.

     NSString *str1 = [str substringToIndex:];

     // 从指定位置开始(包括自定位置的字符串)一直到最后

     NSString *str2 = [str substringFromIndex:];

     // 按照所给定的位置和长度,任意的从字符串中截取新的字符串

     NSString *str3 = [str substringWithRange:NSMakeRange(, )];

     NSLog(@"str1:%@,str2:%@,str3:%@",str1,str2,str3);

 }

 // 可变字符串的操作

 - (void)NSMutableStringOperation

 {

     // 给字符串分配容量

     NSMutableString *strM = [NSMutableString stringWithCapacity:];

     NSLog(@"strM:%@",strM);

     // 在已有的字符串后面添加字符串

     NSMutableString *strM1 = [[NSMutableString alloc] initWithString:@"This is a"];

     NSLog(@"strM1:%@",strM1);

     [strM1 appendString:@"NSMutableString"];

     NSLog(@"strM1:%@",strM1);

     // 在已有字符串中按照所给出的范围和长度删除字符

     [strM1 deleteCharactersInRange:NSMakeRange(, )];

     NSLog(@"strM1:%@",strM1);

     // 在字符串指定位置插入字符串

     [strM1 insertString:@"Hello" atIndex:];

     NSLog(@"strM1:%@",strM1);

     // 将已有字符串替换成其他字符串

     [strM1 setString:@"Hello World"];

     NSLog(@"strM1:%@",strM1);

     // 按照所给出的范围,用新字符串替换原来的字符串

     [strM1 replaceCharactersInRange:NSMakeRange(, ) withString:@"Hi"];

     NSLog(@"strM1:%@",strM1);

 }

 // 时间操作

 - (void)NSDateOperation

 {

     // 得到当前日期

     NSDate *date1 = [NSDate date];

     NSLog(@"date:%@",date1);

     NSDate *date2 = [NSDate dateWithTimeIntervalSinceNow:];

     // 比较日期:

     // <1> 比较日期是否相同

     BOOL result =[date1 isEqualToDate:date2];

     // <2> 比较日期 返回时间较早的日期

     NSDate *dateE = [date1 earlierDate:date2];

     // <3> 比较日期 返回时间较晚的日期

     NSDate *dateL = [date1 laterDate:date2];

     NSLog(@"result:%d, dateE:%@, dateL:%@",result,dateE,dateL);

     // 设置日期的格式

     NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

     // 设置几种默认的显示效果

     [formatter setTimeStyle:NSDateFormatterMediumStyle];

     //自定义日期显示效果

     [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

     NSString *time = [formatter stringFromDate:date1];

     NSLog(@"%@",time);

 }

Math

// 常用常数

-(void)mathConstant

{

    #define M_E         2.71828182845904523536028747135266250   /* e              */

    #define M_LOG2E     1.44269504088896340735992468100189214   /* log2(e)        */

    #define M_LOG10E    0.434294481903251827651128918916605082  /* log10(e)       */

    #define M_LN2       0.693147180559945309417232121458176568  /* loge(2)        */

    #define M_LN10      2.30258509299404568401799145468436421   /* loge(10)       */

    #define M_PI        3.14159265358979323846264338327950288   /* pi             */

    #define M_PI_2      1.57079632679489661923132169163975144   /* pi/2           */

    #define M_PI_4      0.785398163397448309615660845819875721  /* pi/4           */

    #define M_1_PI      0.318309886183790671537767526745028724  /* 1/pi           */

    #define M_2_PI      0.636619772367581343075535053490057448  /* 2/pi           */

    #define M_2_SQRTPI  1.12837916709551257389615890312154517   /* 2/sqrt(pi)     */

    #define M_SQRT2     1.41421356237309504880168872420969808   /* sqrt(2)        */

    #define M_SQRT1_2   0.707106781186547524400844362104849039  /* 1/sqrt(2)      */

}

// 常用函数

- (void)mathFunc

{

    // <1> 指数运算

    NSLog(@"%.f",pow(, )); //

    NSLog(@"%.f",pow(, )); //8

    // <2> 开平方运算(计算两点之间的距离)

    NSLog(@"%.f",sqrt()); //

    NSLog(@"%.f",sqrt()); // 9

    // <3> 四舍五入

    NSLog(@"round:%.f",round( 3.5)); //

    NSLog(@"round:%.f",round(-3.5)); // -4

    // <4> 上舍入

    NSLog(@"ceil:%f",ceil(3.00001)); //

    NSLog(@"ceil:%f",ceil(3.00000)); // 3

    // <5> 下舍入

    NSLog(@"res:%f",floor(3.00001)); //

    NSLog(@"res:%f",floor(3.99999)); // 3

    // <6> 最小值

    NSLog(@"min:%f",fmin(, )); // 5

    // <7> 最大值

    NSLog(@"max:%f",fmax(, )); // 11

    // <8> 绝对值

    NSLog(@"abs:%d",abs(-)); //

    NSLog(@"fabs:%f",fabs(-5.5)); // 5.5

}