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我目前正在编写一个 Android 支票编写器程序，它获取用户输入(阿拉伯数字)并将其转换为支票样式的数字。比如说四千五 block 钱，只有一分钱，诸如此类。英语部分有点简单，我完成了。现在我在不同的 Activity 中写中文版。这次我用了递归算法，因为中文数字写法很不一样。这是算法:(评论是翻译)
private String convertNumberString(String number) {
if (number.equals ("")) {
return "請輸入幣值"; //Please enter amount
}
String[] twoParts = number.split ("\\.");
String integerPart = twoParts[0];
String decimalPart;
try {
decimalPart = twoParts[1];
} catch (ArrayIndexOutOfBoundsException ex) {
decimalPart = "";
}
if (new BigInteger (integerPart).compareTo (new BigInteger ("9999999999999999")) > 0) {
return "輸入的幣值過大，必須小於或等於 9999999999999999"; //The amount is too large, must be less than or equal to 9999999999999999
}
if (new BigInteger (integerPart).compareTo (new BigInteger ("1")) < 0) {
return "輸入的幣值過小，必須大於或等於 1"; //The amount is too small, must be greater than or equal to 1
}
String integerString;
String decimalString = "";
integerString = convertInteger (integerPart);
if (decimalPart.equals ("") || Integer.parseInt (decimalPart) == 0) {
decimalString = "";
} else {
if (decimalPart.length () < 2) {
decimalPart += "0";
}
String jiao = decimalPart.substring (0, 1); //jiao = 角
String fen = decimalPart.substring (1, 2); // fen = 分
if (!jiao.equals ("0")) {
decimalString += convertNumber (getDigitFromString (jiao, 0)) + "角"; // 角 = 10 cents 分 = 1 cent
}
if (!fen.equals ("0")) {
decimalString += convertNumber (getDigitFromString (fen, 0)) + "分";
}
}
return integerString + "圓" + decimalString + "正"; //圓 = dollars 正 = only
}
private String convertNumber (int i) {
switch (i) {
case 0:
return "零"; //zero
case 1:
return "壹"; //one
case 2:
return "貳"; //you get the idea...
case 3:
return "叁";
case 4:
return "肆";
case 5:
return "伍";
case 6:
return "陸";
case 7:
return "柒";
case 8:
return "捌";
case 9:
return "玖";
default:
return "";
}
}
private String getThatWord (int index) {
switch (index) {
case 0:
return "";
case 1:
return "拾"; //ten
case 2:
return "佰"; //hundred
case 3:
return "仟"; //thousand
case 4:
return "萬"; //ten thousand
case 5:
return "億"; //hundred million
case 6:
return "兆";//trillion
default:
return ""; //I know, Chinese numbers are different.
}
}
//here is the recursive part
private String convertInteger (String number) {
if (number.length () < 5) {
if (number.length () == 1)
return convertNumber (getDigitFromString (number, 0));
String finalString = convertNumber (getDigitFromString (number, 0)) +
getThatWord (number.length () - 1);
number = number.substring (1);
if (Integer.parseInt (number) == 0) {
return finalString;
}
for (int i = 0 ; i < number.length () ; i++) {
if (number.charAt (i) == '0')
continue;
return finalString + convertInteger (number.substring (i));
}
return null;
} else {
int charsToRead = number.length () % 4;
if (charsToRead == 0) charsToRead = 4;
String firstPart = number.substring (0, charsToRead);
String secondPart = number.substring (charsToRead);
int thatWordIndex = 3 + number.length () / 4;
if (charsToRead == 4) {
thatWordIndex--;
}
String thatWord = getThatWord (thatWordIndex);
return convertInteger (firstPart) + thatWord + convertInteger (secondPart);
}
}
private int getDigitFromString (String str, int index) {
return Integer.parseInt (Character.toString (str.charAt (index)));
}
如您所见，我有一个递归方法。它转换第一个数字并调用自己转换其余数字。所以如果有一个非常大的数字，它会调用自己很多次。所以我想问一下，在 StackOverflowError 发生之前，一个方法可以调用多少次？