【深入浅出Objective-C】8.4数据(NSData)和8.5数字(NSNumber)

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#import <Foundation/Foundation.h>int main(int argc, const char * argv[]){    @autoreleasepool {        NSString *aPath = @"/Users/chenliang/DeskTop/desktop.ini";        NSData * aData = [NSData dataWithContentsOfFile:aPath];        void *pTest = malloc(100);        NSData *bData = [NSData dataWithBytes:pTest length:100];        NSData *cData = [@"hello" dataUsingEncoding:NSUTF8StringEncoding];                //NSNumber        NSNumber *aIntNumber = [NSNumber numberWithInt:10];        NSNumber *bFloatNumber = [NSNumber numberWithFloat:10.12f];        NSNumber *cBoolNumber = [NSNumber numberWithBool:YES];        NSNumber *dCharNumber = [NSNumber numberWithChar:'a'];        NSLog(@"%@ %@ %@ %@",aIntNumber,bFloatNumber,cBoolNumber,dCharNumber);//10 10.12 1 97                int aInt = [aIntNumber intValue];        float bFloat = [bFloatNumber floatValue];        BOOL cBool = [cBoolNumber boolValue];        char dChar = [dCharNumber charValue];        char *aString = malloc(1);        *aString = dChar;        NSLog(@"%d %.2f %d %s",aInt,bFloat,cBool,aString);//10 10.12 1 a        free(aString);                //简单的运算NSNumber的子类NSDecimalNumber        //9后11个零        NSDecimalNumber *aNumber = [NSDecimalNumber decimalNumberWithString:@"9e11"];        NSDecimalNumber *bNumber = [NSDecimalNumber decimalNumberWithMantissa:9 exponent:11 isNegative:NO];        NSLog(@"aNumber = %@",aNumber);        NSLog(@"bNumber = %@",bNumber);        NSLog(@"%@",[aNumber decimalNumberByAdding:bNumber]);//相加        //以NSNumber的方式来初始化NSDecimalNumber对象        aNumber = (NSDecimalNumber *)[NSDecimalNumber numberWithFloat:1280.21];        bNumber = (NSDecimalNumber *)[NSDecimalNumber numberWithInt:128];        NSLog(@"aNumber = %@",aNumber);        NSLog(@"bNumber = %@",bNumber);        NSLog(@"%@",[aNumber decimalNumberBySubtracting:bNumber]);//相减                //数字格式        NSNumberFormatter *format = [[NSNumberFormatter alloc]init];        NSNumber *numberTest = [NSNumber numberWithDouble:11122223333444.321321];        [format setNumberStyle:NSNumberFormatterDecimalStyle];        NSLog(@"NSNumberFormatterDecimalStyle = %@",[format stringFromNumber:numberTest]);//11,122,223,333,444.3                [format setNumberStyle:NSNumberFormatterNoStyle];//无格式        NSLog(@"NSNumberFormatterNoStyle = %@",[format stringFromNumber:numberTest]);//11122223333444                [format setNumberStyle:NSNumberFormatterCurrencyStyle];//货币        NSLog(@"NSNumberFormatterCurrencyStyle = %@",[format stringFromNumber:numberTest]);//￥11,122,223,333,444.30                [format setRoundingMode:NSNumberFormatterRoundDown];        [format setPositiveFormat:@"#,##0.###"];//#表示预设值，当数字没有此位时则舍去不补位，0表示位数，当数字没有此位时会以0去补位        NSNumber *n = [NSNumber numberWithFloat:123456.3211f];        NSLog(@"setPositiveFormat = %@",[format stringFromNumber:n]);//123,456.32                [format setPositiveFormat:@"0.##"];        NSLog(@"setPositiveFormat = %@",[format stringFromNumber:n]);//123456.32                [format setPositiveFormat:@"0.####"];        NSLog(@"setPositiveFormat = %@",[format stringFromNumber:n]);//123456.3203                [format setPositiveFormat:@"0.00"];        NSLog(@"setPositiveFormat = %@",[format stringFromNumber:n]);//123456.32                [format setPositiveFormat:@"0.0000"];        NSLog(@"setPositiveFormat = %@",[format stringFromNumber:n]);//123456.3203                        //NSNumberFormatterPercentStyle 百分号        //NSNumberFormatterScientificStyle 科学技术法        //NSNumberFormatterSpellOutStyle 拼写        //NSNumberFormatterDecimalStyle 十进制            }    return 0;}
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