Objective-C Numbers_IOS_移动技术网

Objective-C Numbers

In Objective-C programming language, in order to save the basic data types like int, float, bool in object form,

Objective-C provides a range of methods to work with NSNumber and important ones are listed in following table.

S.N.	Method and Description
1	*+ (NSNumber )numberWithBool:(BOOL)value** Creates and returns an NSNumber object containing a given value, treating it as a BOOL.
2	*+ (NSNumber )numberWithChar:(char)value** Creates and returns an NSNumber object containing a given value, treating it as a signed char.
3	*+ (NSNumber )numberWithDouble:(double)value** Creates and returns an NSNumber object containing a given value, treating it as a double.
4	*+ (NSNumber )numberWithFloat:(float)value** Creates and returns an NSNumber object containing a given value, treating it as a float.
5	*+ (NSNumber )numberWithInt:(int)value** Creates and returns an NSNumber object containing a given value, treating it as a signed int.
6	*+ (NSNumber )numberWithInteger:(NSInteger)value** Creates and returns an NSNumber object containing a given value, treating it as an NSInteger.
7	- (BOOL)boolValue Returns the receiver's value as a BOOL.
8	- (char)charValue Returns the receiver's value as a char.
9	- (double)doubleValue Returns the receiver's value as a double.
10	- (float)floatValue Returns the receiver's value as a float.
11	- (NSInteger)integerValue Returns the receiver's value as an NSInteger.
12	- (int)intValue Returns the receiver's value as an int.
13	*- (NSString )stringValue** Returns the receiver's value as a human-readable string.

Here is a simple example for using NSNumber which multiplies two numbers and returns the product.

 1 #import <Foundation/Foundation.h>
 2 
 3 @interface SampleClass:NSObject
 4 
 5 - (NSNumber *)multiplyA:(NSNumber *)a withB:(NSNumber *)b;
 6 
 7 @end
 8 
 9 @implementation SampleClass
10 
11 - (NSNumber *)multiplyA:(NSNumber *)a withB:(NSNumber *)b
12 {
13    float number1 = [a floatValue];
14    float number2 = [b floatValue];
15    float product = number1 * number2;
16    NSNumber *result = [NSNumber numberWithFloat:product];
17    return result;
18 }
19 
20 @end
21 
22 int main()
23 {
24    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
25 
26    SampleClass *sampleClass = [[SampleClass alloc]init];
27    NSNumber *a = [NSNumber numberWithFloat:10.5];
28    NSNumber *b = [NSNumber numberWithFloat:10.0];   
29    NSNumber *result = [sampleClass multiplyA:a withB:b];
30    NSString *resultString = [result stringValue];
31    NSLog(@"The product is %@",resultString);
32 
33    [pool drain];
34    return 0;
35 }

Now when we compile and run the program, we will get the following result.

1 2013-09-14 18:53:40.575 demo[16787] The product is 105