四舍五入相关方案

数字四舍五入方案

方案1:

+ (NSString *)rounding:(float)value afterPoint:(int)position{
   NSDecimalNumberHandler* round_handler = [NSDecimalNumberHandler  decimalNumberHandlerWithRoundingMode: NSRoundPlain scale:position raiseOnExactness:NO raiseOnOverflow:NO raiseOnUnderflow:NO raiseOnDivideByZero:NO];    
  NSDecimalNumber  *  decimal_number = [[NSDecimalNumber alloc] initWithFloat:value];
  NSDecimalNumber * round_number = [decimal_number decimalNumberByRoundingAccordingToBehavior:round_handler];
   return [NSString stringWithFormat:@"%@",round_number];
}

参数：value：要四舍五入的小数
position:保留小数点后几位数字。

重要属性：
NSRoundPlain, //取整
NSRoundDown, // 只舍不入
NSRoundUp, // 只入不舍
NSRoundBankers //四舍五入

方案二
1、round(12345.6789) 结果为：12346
2、round(12345.6789*100)/100 结果为：12345.68