Absolute value of NSInteger

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花落未央
花落未央 2021-02-11 15:29

Referring to Convert to absolute value in Objective-C I\'m wondering if there are functions for NS typedefed types. Or is abs(NSInteger) okay? Is it architecture-sa

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  •  暗喜
    暗喜 (楼主)
    2021-02-11 15:50

    While the two posted answers are absolutely correct about using the ABS() macro, it should certainly be noted that NSIntegerMin, whose true absolute value can not be represented as an NSInteger returns itself when the ABS() function is called.

    Presuming a 64-bit system:

    NSLog(@"ld", ABS(NSIntegerMin)); 
    // prints: -9223372036854775808
    
    NSLog(@"%ld", ABS(NSIntegerMin + 1)); 
    // prints: 9223372036854775807, which == NSIntegerMax
    

    The same results will happen on a 32-bit system, but the numbers will be +2147483647 and -2147483648

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