英文:
Java: How do you get a byte[] array to return hardcoded numbers and what is it that it's currently returning?
问题
以下是翻译后的代码部分：
byte[] b = {'7', '8', '9'};
MegaInt num4 = new MegaInt(b, false);
public MegaInt(byte[] inDigits, boolean isNeg) {
inDigits.toString();
digits = new byte[inDigits.length];
for (int i = 0; i < inDigits.length; i++) {
digits[i] = inDigits[i];
}
if (digits == null || digits.length == 0 || (digits[0] == digits.length && digits[0] == '-')) {
throw new IllegalArgumentException(s);
}
int validIndex = 0;
int leadingZeroCount = 0;
boolean leadingZero = true;
int stringLength = digits.length;
for (int j = 0; j < digits.length; j++) {
System.out.print(digits[j] + ", ");
}
isNegative = isNeg;
for (int i = 0; i < stringLength; i++) {
byte b = digits[i];
System.out.println(b);
if (!isValidDigit(b)) {
throw new IllegalArgumentException(s);
}
if (leadingZero) {
if (b != '0') {
digits = new byte[stringLength - leadingZeroCount];
digits[validIndex] = (byte) Character.getNumericValue(b);
leadingZero = false;
} else {
leadingZeroCount++;
}
} else {
validIndex++;
digits[validIndex] = (byte) Character.getNumericValue(b);
}
}
if (leadingZero) {
digits = new byte[1];
digits[0] = 0;
isNegative = false;
}
}
private boolean isValidDigit(byte b) {
byte[] search = {1, 2, 3, 4, 5, 6, 7, 8, 9, 0};
for (int j = 0; j < search.length; j++) {
if (b == search[j]) {
return true;
}
}
return false;
}
此外，您提到代码返回了 "55,56,57,55"，这实际上是字符编码的ASCII值，而不是您想要的数字。可能是因为在您的打印语句中，将字符直接与数字相加，导致ASCII值输出。如果要打印数字而不是字符的ASCII值，您可以使用以下方式进行修改：
将这行代码：
System.out.print(digits[j] + ", ");
修改为：
System.out.print((char) digits[j] + ", ");
将这行代码：
System.out.println(b);
修改为：
System.out.println((char) b);
这样做会将ASCII值转换为字符，并输出您所需的数字。
英文:
I have hard-coded a byte array (it has to be bytes and not integers for space reasons) and have called it to a constructor that takes a byte array:
this is my byte[] and the constructor from the test file.
byte[] b = {'7','8','9'};
MegaInt num4 = new MegaInt(b, false); //the second parameter is just a boolean to see if the number is negative or not
this is where it is called from the constructor in the class file:
public MegaInt(byte[] inDigits, boolean isNeg)
{
inDigits.toString(); //tried turning to string here but doesn't make a difference
digits = new byte[inDigits.length]; //digits is a class (static final) variable
for (int i = 0; i < inDigits.length; i++)
{
digits[i] = inDigits[i];
}
if(digits == null || digits.length == 0 || (digits[0] == digits.length && digits[0] == digits['-']))
{
throw new IllegalArgumentException(s);
}
int validIndex = 0;
int leadingZeroCount = 0;
boolean leadingZero = true;
int stringLength = digits.length;
for (int j = 0; j < digits.length; j++)
{
System.out.print(digits[j] + ", "); //printing from here
}
isNegative = isNeg; //should this be elsewhere?
for (int i = 0; i < stringLength; i++)
{
byte b = digits[i]; //does not work for charAt
System.out.println(b);
if(!isValidDigit(b)) //gets here and throws exception because of the '55'.
{
throw new IllegalArgumentException(s);
}
if (leadingZero)
{
if (b != '0')
{
digits = new byte[stringLength - leadingZeroCount];
digits[validIndex] = (byte)Character.getNumericValue(b);
leadingZero = false;
}
else
{
leadingZeroCount++;
}
}
else
{
validIndex++;
digits[validIndex] = (byte)Character.getNumericValue(b);
}
}
if (leadingZero) //if there is only 1 zero in the array.
{
digits = new byte[1];
digits[0] = 0;
isNegative = false;
}
private boolean isValidDigit(byte b) //checks if digits are proper for Byte constructors.
{
byte[] search = {1,2,3,4,5,6,7,8,9,0};
for (int j = 0; j < search.length; j++)
{
if (b == search[j])
{
return true; //for valid digits.
}
}
return false;
}
this is what it is returning:
55,56,57,55
I figure this must be some sort of byte representation (I don't think it's binary or hex?) but obviously this is not what I want, how do I get it to use the numbers I have hard-coded? OR am I initializing the byte array properly? Why is it returning 4 numbers when the array only has three? I feel like this is a very simple problem and yet I am finding nothing relevant online so I hope there is someone who can help!
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