遞歸函數返回undefined

Question

我有一個計算稅款的函數。

function taxes(tax, taxWage) 
{ 
    var minWage = firstTier; //defined as a global variable which is not 2299. 
    if (taxWage > minWage) 
    { 
     \\calculates tax recursively calling two other functions difference() and taxStep() 
     tax = tax + difference(taxWage) * taxStep(taxWage); 
     var newSalary = taxWage - difference(taxWage); 
     taxes(tax, newSalary); 
    } 
    else 
    { 
     returnTax = tax + taxWage * taxStep(taxWage); 
     return returnTax; 
    } 
} 

我看不出爲什麼它不會停止遞歸。

Answer 1

在這個臂你的函數：

if (taxWage > minWage) { 
    // calculates tax recursively calling two other functions difference() and taxStep() 
    tax = tax + difference(taxWage) * taxStep(taxWage); 
    var newSalary = taxWage - difference(taxWage); 
    taxes(tax, newSalary); 
} 

你是不是從函數返回一個值或設置returnTax。當您不返回任何內容時，返回值爲undefined。

也許，你想這樣：

if (taxWage > minWage) { 
    // calculates tax recursively calling two other functions difference() and taxStep() 
    tax = tax + difference(taxWage) * taxStep(taxWage); 
    var newSalary = taxWage - difference(taxWage); 
    return taxes(tax, newSalary); 
} 

Answer 2

沒有您的遞歸的錯誤：

taxes(tax, newSalary); 

當if條件的計算結果爲true，不返回任何東西。您需要更改到：

return taxes(tax, newSalary); 

你必須在else必要return聲明。