Objective-C Numbers/數字

在Objective-C編程語言，爲了保存的基本數據類型，如整型，浮點型，布爾對象的形式，

Objective-C中提供了一系列的NSNumber和重要的工作方法是下表中列出。

S.N.

方法和說明

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.

下面是一個簡單的例子，使用的NSNumber兩個數字相乘，並返回該產品。

#import <Foundation/Foundation.h> @interface SampleClass:NSObject - (NSNumber *)multiplyA:(NSNumber *)a withB:(NSNumber *)b; @end @implementation SampleClass - (NSNumber *)multiplyA:(NSNumber *)a withB:(NSNumber *)b { float number1 = [a floatValue]; float number2 = [b floatValue]; float product = number1 * number2; NSNumber *result = [NSNumber numberWithFloat:product]; return result; } @end int main() { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; SampleClass *sampleClass = [[SampleClass alloc]init]; NSNumber *a = [NSNumber numberWithFloat:10.5]; NSNumber *b = [NSNumber numberWithFloat:10.0]; NSNumber *result = [sampleClass multiplyA:a withB:b]; NSString *resultString = [result stringValue]; NSLog(@"The product is %@",resultString); [pool drain]; return 0; }

現在，當我們編譯並運行程序，我們會得到以下的結果。

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