iOS 人民币单位转换，元 转 万元 转 亿，等等。

- (NSString *)getDealNumwithstring:(NSString *)string withNumCount:(NSInteger)integer{
    
    
    NSDecimalNumber *numberA = [NSDecimalNumber decimalNumberWithString:string];
    NSDecimalNumber *numberB ;
    if (integer == 4) {
        numberB =  [NSDecimalNumber decimalNumberWithString:@"10000"];
    } else if (integer == 8){
        numberB =  [NSDecimalNumber decimalNumberWithString:@"100000000"];
    }else{
        numberB =  [NSDecimalNumber decimalNumberWithString:@"10000"];
    }
    //NSDecimalNumberBehaviors对象的创建  参数 1.RoundingMode 一个取舍枚举值 2.scale 处理范围 3.raiseOnExactness  精确出现异常是否抛出原因 4.raiseOnOverflow  上溢出是否抛出原因  4.raiseOnUnderflow  下溢出是否抛出原因  5.raiseOnDivideByZero  除以0是否抛出原因。
    NSDecimalNumberHandler *roundingBehavior = [NSDecimalNumberHandler decimalNumberHandlerWithRoundingMode:NSRoundDown scale:2 raiseOnExactness:NO raiseOnOverflow:NO raiseOnUnderflow:NO raiseOnDivideByZero:NO];
    
    /// 这里不仅包含Multiply还有加 减 乘。
    NSDecimalNumber *numResult = [numberA decimalNumberByDividingBy:numberB withBehavior:roundingBehavior];
    NSString *strResult = [numResult stringValue];
    return strResult;
}