Object-c-foundation-nsnuber

NSNumber is a numeric value that is encapsulated by a numeric type.

Boxing: Object type, base type

NSNumber *number=[nsnumber Numberwithint:12];

Unboxing: Object Type--object type

int a = [num intvalue];

Nsinteger

Nsvalue is a NSNumber parent class that encapsulates a struct as an object

Nsrange range;

Range.location=1; range.length=5;

Packing

Nsvalue *value=[nsvalue Valuewithrange:range]

Nsrange Range2;

Unpacking

[Value getvalue:&range2];

You can customize the structure of a type rect to struct-body variable myrect to struct-body name

Nsvalue *rectvalue =[nsvalue valuewithbytes:&rect objctype:encode (myrect)];

NSNull Package Nil

Nsarray *arr =[nsarray arraywithobjects:@ "Tom", [NSNull Null],nil];

for (int i=0; I<[arr count]; i++) {}

Object-c-foundation-nsnuber