成交量与指标副图重叠以及value (NaN, or not-a-number)

[472647301]

成交量视图重叠应该是没有else的原因

if(_secondaryState != SecondaryStateNONE) {
      _seconderyRender = [[SecondaryChartRenderer alloc] initWithMaxValue:_mSecondaryMaxValue 
      minValue:_mSecondaryMinValue chartRect:_secondaryRect candleWidth:_candleWidth 
      topPadding:ChartStyle_childPadding state:_secondaryState];
    } else {
      _seconderyRender = nil;
    }

value (NaN, or not-a-number)

double rsv = 0;
    if (max14 - min14 != 0) {
        rsv = 100 * (closePrice - min14) / (max14 - min14);
      }

我只是个iOS初学者，不知道这样处理是否正确？