Detailed NSNumber usage in Objective-C

In Objective-c, there is an int data type. Why do we need to use the numeric object NSNumber? This is because many classes (such as NSArray) require the use of objects, whereas int is not an object.
NSNumber is a numeric object. We can use the NSNumber object to create and initialize different types of numeric objects.

For example:

 

[Cpp]View plaincopy

1. # Import <Foundation/Foundation. h>
2.   
3. NSNumber * myNumber, * floatNumber, * intNumber, * number1;
4.   
5. // Create an integer object
6. IntNumber = [NSNumber numberWithInteger: 123];
7. NSLog (@ "% I", [intNumber integerValue]);
8.   
9. // Create a long object
10. MyNumber = [NSNumber numberWithLong: 0 xababab];
11. NSLog (@ "% lx", [myNumber longValue]);
12.   
13. // Create a char object
14. MyNumber = [NSNumber numberWithChar: 'K'];
15. NSLog (@ "% c", [myNumber charValue]);
16.   
17. // Create a float object
18. FloatNumber = [NSNumber numberWithFloat: 123.00];
19. NSLog (@ "% f", [floatNumber floatValue]);
20.   
21. // Create a double object
22. MyNumber = [NSNumber numberWithDouble: 112233e + 15];
23. NSLog (@ "% lg", [myNumber doubleValue]);
24.   
25. // Determine whether the values of the two objects are equal
26. If ([intNumber isw.tonumber: floatNumber] = YES ){
27. NSLog (@ "equal value ");
28. } Else {
29. NSLog (@ "The value is not equal ");
30. }  
31.   
32. // Compare the values of two objects
33. If ([intNumber compare: myNumber] = NSOrderedAscending ){
34. NSLog (@ "small number on the left ");
35. } Else {
36. NSLog (@ "the number on the left ");
37. }  
38.   
39. // Initialize the instance
40. Number1 = [[NSNumber alloc] initWithInt: 1000];
41. NSLog (@ "% d", [number1 intValueunsigned];
42. [Number1 release];

For each basic type, the class method assigns an NSNumber object to it and sets it to the specified value. These methods start with numberWith, followed by the type, such as numberWithLong.
In addition, you can also use the instance method to set the specified value for the NSNumber object previously allocated, all of which start with initWith, such as initWithLong.

 

For example:

 

Create and initialize class methods	Instance initialization method	Value instance method
NumberWithChar:	InitWithChar:	CharValue
NumberWithShort:	InitWithShort:	ShortValue
...	...	...

 

Detailed NSNumber usage in Objective-C