将多个浮点值汇总为新的浮点（双精度值）

Question

如何将多个doubleValue求和成一个新的double？ 目前，我已经尝试过这样：

double sum = doubleWantToSum1 + doubleWantToSum2 + doubleWantToSum; //etc...

此外，我想将结果用于此等式

double tooMuch = sum - 100;

我要返回100减去浮动金额的总和。 目前，唯一要做的就是输出doubleWantToSum1-100。我相信答案很简单，但是由于我在互联网上找不到任何关于此的答案，如果你们中的一个告诉我，我会喜欢的。

编辑，添加代码注意，我知道这很糟糕，可能无效。

//Nummerformatterere - Kinda unødvendig
NSNumberFormatter *fmt1  =  [NSNumberFormatter new]; //Temp
NSNumberFormatter *fmt2  =  [NSNumberFormatter new]; //Methane
NSNumberFormatter *fmt3  =  [NSNumberFormatter new]; //Ethane
NSNumberFormatter *fmt4  =  [NSNumberFormatter new]; //Propane
NSNumberFormatter *fmt5  =  [NSNumberFormatter new]; //n-butane
NSNumberFormatter *fmt6  =  [NSNumberFormatter new]; //i-butane
NSNumberFormatter *fmt7  =  [NSNumberFormatter new]; //n-petane
NSNumberFormatter *fmt8  =  [NSNumberFormatter new]; //i-petane
NSNumberFormatter *fmt9  =  [NSNumberFormatter new]; //n-hexane
NSNumberFormatter *fmt10 =  [NSNumberFormatter new]; //nitrogen
NSNumberFormatter *fmt11 =  [NSNumberFormatter new]; //oxygen

//Float for å få textfieldsene til nummer
double temprature = [fmt1  numberFromString: tempratureText.text].doubleValue;
double methane    = [fmt2  numberFromString: methaneText.text   ].doubleValue;
double ethane     = [fmt3  numberFromString: ethaneText.text    ].doubleValue;
double propane    = [fmt4  numberFromString: propaneText.text   ].doubleValue;
double nbutane    = [fmt5  numberFromString: nbutaneText.text   ].doubleValue;
double ibutane    = [fmt6  numberFromString: ibutaneText.text   ].doubleValue;
double npetane    = [fmt7  numberFromString: npetaneText.text   ].doubleValue;
double ipetane    = [fmt8  numberFromString: ipetaneText.text   ].doubleValue;
double nhexane    = [fmt9  numberFromString: nhexaneText.text   ].doubleValue;
double nitrogen   = [fmt10 numberFromString: nitrogenText.text  ].doubleValue;
double oxygen     = [fmt11 numberFromString: oxygenText.text    ].doubleValue;

//Floats og formatters for underflow, overflow
double sum = (methane + ethane + propane + nbutane + ibutane + npetane + ipetane + nhexane + nitrogen + oxygen);
double overflowPart = 100 - sum;
double underflowPart = sum - 100;

NSNumber *underFlow = [[NSNumber alloc]initWithDouble:underflowPart];
NSNumberFormatter *underFlowResult = [[NSNumberFormatter alloc] init];
underFlowResult.numberStyle = NSNumberFormatterDecimalStyle;
[underFlowResult setNumberStyle:NSNumberFormatterDecimalStyle];
[underFlowResult setMaximumFractionDigits:2];
NSString *formattedUnderFlow = [underFlowResult stringFromNumber:(NSNumber*)underFlow];

NSNumber *overFlow = [[NSNumber alloc]initWithDouble:underflowPart];
NSNumberFormatter *overFlowResult = [[NSNumberFormatter alloc] init];
overFlowResult.numberStyle = NSNumberFormatterDecimalStyle;
[overFlowResult setNumberStyle:NSNumberFormatterDecimalStyle];
[overFlowResult setMaximumFractionDigits:2];

NSString *formattedOverFlow = [overFlowResult stringFromNumber:(NSNumber*)overFlow];

//Floats for variabler til ligningen
double Xi = 1;
double Mi = 2;
double Vi = 3;
double Vc = 4;

//Ligningen for å regne ut density
double over1 = Xi * Mi;
double under1 = Xi * Vi - Vc;

//=RESULT=
double result =  over1 / under1;

/*----------STREK FORDI DET ER CHILL OG JEG ER FERDIG MED FLOATER----------*/

NSString *resultString = [[NSString alloc]initWithFormat:@"D = %f", result];
NSString *overflowString = [[NSString alloc]initWithFormat:@"Total %@ greater than 100 %", formattedOverFlow ];
NSString *underflowString = [[NSString alloc]initWithFormat:@"Total %@ less than 100 %", formattedUnderFlow];

/*----------STREK FORDI DET ER CHILL OG JEG ER FERDIG MED STRINGS----------*/
/*
if (temprature == 0 || methane == 0 || ethane == 0 || propane == 0 || nbutane == 0 || ibutane == 0 || oxygen == 0 || npetane == 0 || ipetane == 0 || nhexane == 0 || nitrogen == 0)
{
    outputText.text = @"Please enter all values";
} */
if (underflowPart == 100)
{
    outputText.text = @"Start by entering values above";
}
if (sum == 100)
{
    outputText.text = resultString;
}

if (sum > 100)
{
    outputText.text = overflowString;
}

if (sum < 100)
{
    outputText.text = underflowString;
}
/*----------STREK FORDI DET ER CHILL OG JEG ER FERDIG MED 'if'----------*/

Answer 1

这可能取决于您要添加的数字的大小（精度）。 为了解决这个问题，您可以使用NSDecimalNumber ，它最多可以保留38位十进制数字。

Answer 2

注释中尚未明确指出，您对代码中的数字求和的方式是正确的。 这些注释所隐含的含义是，您求和的数字是错误的，因此应记录它们以了解它们的含义。

同样，您可以使用以下方法保存一些代码（消除数字格式化程序）：

double temprature = [tempratureText.text doubleValue];

代替

double temprature = [fmt1  numberFromString: tempratureText.text].doubleValue;