Algorithm that converts numeric amount into English words

Question

What is the most efficient way to convert numeric amount into English words

e.g. 12 to twelve 127 to one hundred twenty-seven

Answer 1

This is some old python code on my hard drive. There might be bugs but it should show the basic idea:

class Translator:
    def transformInt(self, x):
        translateNumbers(0,[str(x)])

    def threeDigitsNumber(self,number):
        snumber=self.twoDigitsNumber(number/100)
        if number/100!=0:
            snumber+=" hundred "
        snumber+self.twoDigitsNumber(number)
        return snumber+self.twoDigitsNumber(number)
    def twoDigitsNumber(self,number):
        snumber=""
        if number%100==10:
            snumber+="ten"
        elif number%100==11:
            snumber+="eleven"
        elif number%100==12:
            snumber+="twelve"
        elif number%100==13:
            snumber+="thirteen"
        elif number%100==14:
            snumber+="fourteen"
        elif number%100==15:
            snumber+="fifteen"
        elif number%100==16:
            snumber+="sixteen"
        elif number%100==17:
            snumber+="seventeen"
        elif number%100==18:
            snumber+="eighteen"
        elif number%100==19:
            snumber+="nineteen"
        else:
            if (number%100)/10==2:
                snumber+="twenty-"
            elif (number%100)/10==3:
                snumber+="thirty-"
            elif (number%100)/10==4:
                snumber+="forty-"
            elif (number%100)/10==5:
                snumber+="fifty-"
            elif (number%100)/10==6:
                snumber+="sixty-"
            elif (number%100)/10==7:
                snumber+="seventy-"
            elif (number%100)/10==8:
                snumber+="eighty-"
            elif (number%100)/10==9:
                snumber+="ninety-"
            if (number%10)==1:
                snumber+="one"
            elif (number%10)==2:
                snumber+="two"
            elif (number%10)==3:
                snumber+="three"
            elif (number%10)==4:
                snumber+="four"
            elif (number%10)==5:
                snumber+="five"
            elif (number%10)==6:
                snumber+="six"
            elif (number%10)==7:
                snumber+="seven"
            elif (number%10)==8:
                snumber+="eight"
            elif (number%10)==9:
                snumber+="nine"
            elif (number%10)==0:
                if snumber!="":
                    if snumber[len(snumber)-1]=="-":
                        snumber=snumber[0:len(snumber)-1]
        return snumber
    def translateNumbers(self,counter,words):
        if counter+147 and ord(words[counter][k])<58)):
                break
            k+=1
        if (k!=len(words[counter]) or k==0):
            return 1
        number=int(words[counter])
        from copy import copy
        if number==0:
            self.translateNumbers(counter+1,copy(words[0:counter]+["zero"]+words[counter+1:len(words)]))
            self.next.append(copy(words[0:counter]+["zero"]+words[counter+1:len(words)]))
            return 1
        if number<10000:
            self.translateNumbers(counter+1,copy(words[0:counter]
                                                      +self.seperatewords(self.threeDigitsNumber(number))
                                                      +words[counter+1:len(words)]))
            self.next.append(copy(words[0:counter]
                                       +self.seperatewords(self.threeDigitsNumber(number))
                                       +words[counter+1:len(words)]))
        if number>999:
            snumber=""
            if number>1000000000:
                snumber+=self.threeDigitsNumber(number/1000000000)+" billion "
                number=number%1000000000
            if number>1000000:
                snumber+=self.threeDigitsNumber(number/1000000)+" million "
                number=number%1000000
            if number>1000:
                snumber+=self.threeDigitsNumber(number/1000)+" thousand "
                number=number%1000
            snumber+=self.threeDigitsNumber(number)
            self.translateNumbers(counter+1,copy(words[0:counter]+self.seperatewords(snumber)
                                                      +words[counter+1:len(words)]))
            self.next.append(copy(words[0:counter]+self.seperatewords(snumber)
                                       +words[counter+1:len(words)]))