之前已经学习过了基本数据类型。但是这些都市基本数据类型，它们不是对象。因此，不能向它们发送消息。

然后有时也需要将它们当做对象来处理。不如，我们需要把基本数据类型放入到集合中（在Cocoa中集中只能存放对象，

无法存放基本数据类型），那么这时我们需要将基本类型转换成数字对象.OC中提供了数据对象”NSNumber“可以将基本数据

类型”包装“成对象,这样我们就可以将基本数据类型来处理了

下面我们来看下具体使用例子：

//
//  main.m
//  FoundationDemo1
//
//  Created by hmjiangqq on 14-1-23.
//  Copyright (c) 2014年 hmjiangqq. All rights reserved.
//

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[])
{

    @autoreleasepool {
        
        // insert code here...
        NSLog(@"Hello, World!");
        /*===========NSNumber=================*/
         //创建一个NSNumber对象
        NSNumber *monthNumber=[[NSNumber alloc]initWithInt:10];
        NSNumber *lengthNumber=[[NSNumber alloc]initWithFloat:10.8];
        NSLog(@"month =%@\n",monthNumber);
        NSLog(@"length =%@\n",lengthNumber);
        //还原成基本数据类型
        int month=[monthNumber intValue];
        float length=[lengthNumber floatValue];
        NSLog(@"month=%d\n",month);
        NSLog(@"length=%.1f\n",length);
        /*=============NSString====================*/
    }
    return 0;
}

- (id)initWithChar:(char)value;
- (id)initWithUnsignedChar:(unsigned char)value;
- (id)initWithShort:(short)value;
- (id)initWithUnsignedShort:(unsigned short)value;
- (id)initWithInt:(int)value;
- (id)initWithUnsignedInt:(unsigned int)value;
- (id)initWithLong:(long)value;
- (id)initWithUnsignedLong:(unsigned long)value;
- (id)initWithLongLong:(long long)value;
- (id)initWithUnsignedLongLong:(unsigned long long)value;
- (id)initWithFloat:(float)value;
- (id)initWithDouble:(double)value;
- (id)initWithBool:(BOOL)value;
- (id)initWithInteger:(NSInteger)value NS_AVAILABLE(10_5, 2_0);
- (id)initWithUnsignedInteger:(NSUInteger)value NS_AVAILABLE(10_5, 2_0);

- (char)charValue;
- (unsigned char)unsignedCharValue;
- (short)shortValue;
- (unsigned short)unsignedShortValue;
- (int)intValue;
- (unsigned int)unsignedIntValue;
- (long)longValue;
- (unsigned long)unsignedLongValue;
- (long long)longLongValue;
- (unsigned long long)unsignedLongLongValue;
- (float)floatValue;
- (double)doubleValue;
- (BOOL)boolValue;
- (NSInteger)integerValue NS_AVAILABLE(10_5, 2_0);
- (NSUInteger)unsignedIntegerValue NS_AVAILABLE(10_5, 2_0);

+ (NSNumber *)numberWithChar:(char)value;
+ (NSNumber *)numberWithUnsignedChar:(unsigned char)value;
+ (NSNumber *)numberWithShort:(short)value;
+ (NSNumber *)numberWithUnsignedShort:(unsigned short)value;
+ (NSNumber *)numberWithInt:(int)value;
+ (NSNumber *)numberWithUnsignedInt:(unsigned int)value;
+ (NSNumber *)numberWithLong:(long)value;
+ (NSNumber *)numberWithUnsignedLong:(unsigned long)value;
+ (NSNumber *)numberWithLongLong:(long long)value;
+ (NSNumber *)numberWithUnsignedLongLong:(unsigned long long)value;
+ (NSNumber *)numberWithFloat:(float)value;
+ (NSNumber *)numberWithDouble:(double)value;
+ (NSNumber *)numberWithBool:(BOOL)value;
+ (NSNumber *)numberWithInteger:(NSInteger)value NS_AVAILABLE(10_5, 2_0);
+ (NSNumber *)numberWithUnsignedInteger:(NSUInteger)value NS_AVAILABLE(10_5, 2_0);

【Objective-C】OC中NSNumber数字对象的常用处理方法