Golang : How to convert a number to words




I need to translate a given number into words such as 100 to one hundred. The code below is a translation of Christian d'Heureuse's work at http://www.source-code.biz/snippets/java/13.htm. It shows how to convert a number up to billion into words. Here you go! package main import ( "fmt" ) var lowNames = []string{"zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"} var tensNames = []string{"twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"} var bigNames = []string{"thousand", "million", "billion"} func convert999(num int) string { s1 := lowNames[num/100] + " hundred" s2 := convert99(num % 100) if num <= 99 { return s2 } if num0 == 0 { return s1 } else { return s1 + " " + s2 } } func convert99(num int) string { if num < 20 { return lowNames[num] } s := tensNames[num/10-2] if num == 0 { return s } return s + "-" + lowNames[num] } func convertNum2Words(num int) string { if num < 0 { return "negative " + convertNum2Words(-num) } if num <= 999 { return convert999(num) } s := "" t := 0 for num > 0 { if num00 != 0 { s2 := convert999(num % 1000) if t > 0 { s2 = s2 + " " + bigNames[t-1] } if s == "" { s = s2 } else { s = s2 + ", " + s } } num /= 1000 t++ } return s } func main() { fmt.Println("100 in words : ", convertNum2Words(100)) fmt.Println("0123 in words : ", convertNum2Words(0123)) fmt.Println("-99 in words : ", convertNum2Words(-99)) fmt.Println("54312337 in words : ", convertNum2Words(54312337)) fmt.Println("932476182910 in words : ", convertNum2Words(932476182910)) fmt.Println("-932476182910 in words : ", convertNum2Words(-932476182910)) // because we only convert up to billion, any number exceeding 9 zeros will cause // runtime error: index out of range //fmt.Println("9324761829101 in words : " , convertNum2Words(9324761829101)) } Output: 100 in words : one hundred 0123 in words : eighty-three <------ wrong! -99 in words : negative ninety-nine 54312337 in words : fifty-four million, three hundred twelve thousand, three hundred thirty-seven 932476182910 in words : nine hundred thirty-two billion, four hundred seventy-six million, one hundred eighty-two thousand, nine hundred ten -932476182910 in words : negative nine hundred thirty-two billion, four hundred seventy-six million, one hundred eighty-two thousand, nine hundred ten NOTES: You need to put in a sanity checker to test if the input number is a sane number. As demonstrated, having a given number that starts with zero will cause the translation to go crazy. For example, the translation of 0123 to eighty-three just doesn't make sense. How to write the sanity checker? That's the exercise for this tutorial. ;-) Reference: http://www.source-code.biz/snippets/java/13.htm


Tags : golang translate-number-to-words convert-number

Adam Ng By Adam Ng

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