IOS 开发之ObjectiveC的变量类型的字符代表

IOS 开发之ObjectiveC的变量类型的字符代表

实例代码：

NSDictionary *dic = @{@"1":[NSNumber numberWithBool:YES], 
                @"2":[NSNumber numberWithChar:'1'], 
                @"3":[NSNumber numberWithDouble:2.0], 
                @"4":[NSNumber numberWithFloat:2.0f], 
                @"5":[NSNumber numberWithInt:1], 
                @"6":[NSNumber numberWithInteger:2], 
                @"7":[NSNumber numberWithLong:30], 
                @"8":[NSNumber numberWithLongLong:3], 
                @"9":[NSNumber numberWithShort:4], 
                @"10":[NSNumber numberWithUnsignedChar:'1'], 
                @"11":[NSNumber numberWithUnsignedInt:3], 
                @"12":[NSNumber numberWithUnsignedInteger:35], 
                @"13":[NSNumber numberWithUnsignedLong:45], 
                @"14":[NSNumber numberWithUnsignedLongLong:59], 
                @"15":[NSNumber numberWithUnsignedShort:4] 
                }; 
    for(NSString *key in dic){ 
      id value = [dic valueForKey:key]; 
      if([value isKindOfClass:[NSNumber class]]){ 
        const charchar * pObjCType = [((NSNumber*)value) objCType]; 
        NSLog(@"%@,%s",key,pObjCType); 
      } 
    } 

以上的输出结果证明：

UnsignedChar  =>s 
Char      =>c 
UnsignedShort  =>i 
LongLong    =>d 
UnsignedInt   =>q 
Float      =>f 
Int       =>i 
UnsignedInteger =>q 
Integer     =>q 
UnsignedLong  =>q 
Long      =>q 
LongLong    =>q 
UnsignedLongLong=>q 
Bool      =>c 
Short      =>s 
double     =>d 

再看以下代码，用@encode关键字的

NSLog(@"1=>%s",@encode(BOOL)); 
NSLog(@"2=>%s",@encode(char)); 
NSLog(@"3=>%s",@encode(double)); 
NSLog(@"4=>%s",@encode(float)); 
NSLog(@"5=>%s",@encode(int)); 
NSLog(@"6=>%s",@encode(NSInteger)); 
NSLog(@"7=>%s",@encode(long)); 
NSLog(@"8=>%s",@encode(long long)); 
NSLog(@"9=>%s",@encode(short)); 
NSLog(@"10=>%s",@encode(unsigned char)); 
NSLog(@"11=>%s",@encode(unsigned int)); 
NSLog(@"12=>%s",@encode(unsigned long));//unsigned NSInteger 
NSLog(@"13=>%s",@encode(unsigned long)); 
NSLog(@"14=>%s",@encode(unsigned long long)); 
NSLog(@"15=>%s",@encode(unsigned short)); 

以上的输出结果证明：

BOOL=>c 
 char=>c 
 double=>d 
 float=>f 
 int=>i 
 NSInteger=>q 
 long=>q 
 long long=>q 
 short=>s 
 unsigned char=>C 
 unsigned int=>I 
 unsigned NSInteger=>Q 
 unsigned long=>Q 
 unsigned long long=>Q 
 unsigned short=>S 

读者可以根据这种方式来判断某个变量到底属于哪种类型。

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