C中的占位符,打印BOOL类型数据(2)

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Mac OS X uses several data types—NSInteger, NSUInteger,CGFloat, and CFIndex—to provide a consistent means of representing values in 32- and 64-bit environments. In a 32-bit environment, NSInteger and NSUInteger are defined as int and unsigned int, respectively. In 64-bit environments, NSInteger and NSUInteger are defined as long and unsigned long, respectively. To avoid the need to use different printf-style type specifiers depending on the platform, you can use the specifiers shown in Table 2. Note that in some cases you may have to cast the value.

Table 2 Format specifiers for data types 类型   定义   建议  
NSInteger   %ld or %lx   Cast the value to long  
NSUInteger   %lu or %lx   Cast the value to unsigned long  
CGFloat   %f or %g   %f works for floats and doubles when formatting; but see below warning when scanning  
CFIndex   %ld or %lx   The same as NSInteger  
pointer   %p   %p adds 0x to the beginning of the output. If you don’t want that, use %lx and cast to long.  
long long   %lld or %llx   long long is 64-bit on both 32- and 64-bit platforms  
unsigned long long   %llu or %llx   unsigned long long is 64-bit on both 32- and 64-bit platforms  

The following example illustrates the use of %ld to format an NSInteger and the use of a cast.

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