oj 的 go语言运行环境感觉有些问题

package main

import(  "fmt"  "math"
)

func zeroToNineteen(num int64){
        exps := []string{"one","two","three","four","five","six","seven","eight","nine","ten","eleven","twelve","thirteen","fourteen","fivteen","sixteen","seventeen","eighteen","nineteen"}  fmt.Print(exps[num-1])
}

func twentyToNinetyNine(num int64){  if num<20 {  zeroToNineteen(num)  return  }  a,b := num/10,num%10  exps := []string{"twenty","thirty","fourty","fifty","sixty","seventy","eighty","ninety"}  fmt.Print(exps[a-2])  if b!=0 {  fmt.Print(" ")  zeroToNineteen(b)  }
}

func oneHundredTo999(num int64){  if num<100 {  twentyToNinetyNine(num)  return  }  exps := " hundred"  a,b := num/100,num%100  zeroToNineteen(a)  fmt.Print(exps)  if b!=0 {  fmt.Print(" and ")  twentyToNinetyNine(b)  }
}

func oneThousandTo999999(num int64){  if num<1000 {  oneHundredTo999(num)  return  }  exps := " thousand "  a,b := num/1000,num%1000  oneHundredTo999(a)  fmt.Print(exps)  if b!=0 {  oneHundredTo999(b)  }
}

func oneMillionTo999999999(num int64){  if num<1000000 {  oneThousandTo999999(num)  return  }  exps := " million "  a,b := num/1000000,num%1000000  oneHundredTo999(a)  fmt.Print(exps)  if b!=0 {  oneThousandTo999999(b)  }
}


func oneBillionToInt32Max(num int64){  if num<1000000000 {  oneMillionTo999999999(num)  return  }  exps := " billion "  a,b := num/1000000000,num%1000000000  oneHundredTo999(a)  fmt.Print(exps)  if b!=0 {  oneMillionTo999999999(b)  }
}

func numToEng(num int64){  if num==0 {  fmt.Println("zero")  return  }  if num<0 {  fmt.Print("negative ")  }  //注：int64最小值在取绝对值后会发生越界，数字太大这里不单独处理了  num = int64(math.Abs(float64(num)))   if num>1000 && num%1000<100{  num_2 := num%1000  num_1 := num - num_2  oneBillionToInt32Max(num_1)  fmt.Print("and ")  twentyToNinetyNine(num_2)  fmt.Println()  return  }  oneBillionToInt32Max(num)  fmt.Println()   }

func main(){  for{  var num int64  _,err := fmt.Scan(&num);  if err != nil{  fmt.Println("error")  return  }  numToEng(num)  }
}