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标题: Objective-C Numbers [打印本页]

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作者: ZXY66452    时间: 2015-12-7 22:07
标题: Objective-C Numbers

在Objective-C编程语言，为了保存的基本数据类型，如整型，浮点型，布尔对象的形式，

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.        方法和说明
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.
下面是一个简单的例子，使用的NSNumber两个数字相乘，并返回该产品。

#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;
}
现在，当我们编译并运行程序，我们会得到以下的结果。

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

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