我试图调用一个从接口类重写的除法方法。所有类似的方法（加，减，乘）都可以正常工作，除非由于某些原因找不到除法。以下是我的内容：
算术接口类
public interface Arithmetic {
public Object add(Object obj);
public Object subtract(Object obj);
public Object multiply(Object obj);
public Object divide(Object obj);
}
数字类（算术方法在下面被覆盖，除以最后一个）
public class Number implements Comparable,Arithmetic{
/**
* A string representing a non-negative number
*/
private String value;
/**
* An integer greater than or equals to 2.
*/
private int base;
/**
* - for negative numbers and otherwise null
*/
private char sign;
/**
* creates 0 base 2.
*/
public Number()
{
value = "0";
base = 2;
}
/**
* creates a number in a specified based using the specified parameters.
* @param num a string representing a non-negative number with digit
* written in uppercase letters.
* @param radix the base of the number
*/
public Number(String num, int radix) throws InvalidNumberException
{
String list = ".-0123456ABCDEFGHIJKLMNOPQRSTUVWXYZ";
Boolean pars = false;
for (int i = 0; i < list.length(); i++) {
if (num.indexOf(list.charAt(i)) != -1) {
pars = true;
}
}
if (radix < 1 || radix > 35) {
throw new InvalidNumberException("Number invoked with a radix less than 1 or greater than 35.");
} else if ((num.indexOf(".") != num.lastIndexOf(".")) || (num.indexOf("-") != num.lastIndexOf("-"))) {
throw new InvalidNumberException("Number invoked with more than one dash or period in string.");
} else if (num.indexOf("-") != 0) {
throw new InvalidNumberException("Number invoked with dash not at beginning of string.");
} else if (num.indexOf(".") == num.length()) {
throw new InvalidNumberException("Number invoked with period at end of string.");
}
else if (pars == true) {
throw new InvalidNumberException("Number invoked with invalid character.");
}
Boolean test=false;
for (int i = 0; i < num.length(); i++) {
if ((num.charAt(i) != '-') || (num.charAt(i) != '.')) {
if (toValue(num.charAt(i)) >= radix) {
test=true;
throw new InvalidNumberException("Number invoked with digit greater or equal to radix.");
}
}
}
if(test==false){
value = num;
base = radix;
}
}
/**
* Converts a digit to its integer equivalent
* @param digit 0...9 or A...Z to be converted
* @return the integer equivalent of the specified digit.
*/
private int toValue(char digit)
{
return Character.getNumericValue(digit);
}
/**
* Converts this integer to its equivalent digit
* @param anInt an integer between 0-35
* @return the digit equivalent to an integer
*/
private char toDigit(int anInt)
{
if(anInt >= 0 && anInt <= 9)
return (char)(anInt + 48);
else if(anInt >= 10 && anInt <= 35)
return (char)(anInt + 55);
else
return (char)(-1);
}
/**
* converts a number to its decimal equivalent (double).
* @return the decimal equivalent of a number
*/
private double toDouble()
{
if (base == 10)
return Double.parseDouble(value);
int periodIndex = value.indexOf('.');
double base10Num = 0;
int i;
int radix = base;
String whole;
if (periodIndex >=0)
whole = value.substring(0, periodIndex);
else
whole = value;
int j=0;
int wholeLength = whole.length();
for (i=wholeLength-1; i>=0; i--)
base10Num = base10Num + toValue(whole.charAt(i))*(int)Math.pow(radix,wholeLength-i-1);
if (periodIndex >= 0)
{
String fract = value.substring(periodIndex+1,value.length());
int fractLength = fract.length();
for (i=0; i<fractLength; i++)
{
base10Num = base10Num + toValue(fract.charAt(i))*Math.pow(radix,-i-1);
}
}
if (sign == '-')
base10Num *= -1;
return base10Num;
}
/**
* converts a decimal number (double) to its equivalent representation
* in a given base.
* @param dec the decimal (base 10) number
* @radix the base to convert the number to.
* @return the equivalent number in the specified base
*/
private Number doubleToNumber(double dec, int radix)
{
if (radix == 10)
return new Number(Double.toString(dec),radix);
String numSign="";
if (dec < 0)
{
numSign = "-";
dec = -dec;
}
int whole = (int)dec;
double fract = dec - whole;
String numStr = "";
while (whole != 0)
{
numStr = toDigit(whole%radix) + numStr;
whole = whole / radix;
}
if (fract != 0)
{
numStr += ".";
int tolerance = 20;
int precision = 0;
while (precision < tolerance && fract != 0)
{
fract = fract * radix;
numStr += toDigit((int)(fract));
precision++;
fract = fract - (int)fract;
}
}
return new Number(numSign+numStr,radix);
}
/**
* Gives a string representation of this number in the
* format number[base].
* @return a string representation of this number
*/
@Override
public String toString()
{
return String.format("%s%s[%d]", this.sign, this.value, this.base);
}
@Override
public boolean equals(Object obj)
{
if (!(obj instanceof Number))
return false;
return (this.toDouble()==((Number)obj).toDouble());
}
@Override
public int compareTo(Object obj) throws IllegalArgumentException
{
if (!(obj instanceof Number))throw new IllegalArgumentException();
else if(this.toDouble()<((Number)obj).toDouble()) return -1;
else if(this.toDouble()>((Number)obj).toDouble()) return 1;
else return 0;
}
/**
* This method adds two numbers from two different objects
* @param obj the number of the object inputted from user
* @return a new added number object
*/
@Override
public Object add(Object obj) throws IllegalArgumentException {
if (!(obj instanceof Number)) {
throw new IllegalArgumentException();
} else if (this.base != ((Number) obj).base) {
throw new IllegalArgumentException();
} else {
return doubleToNumber((this.toDouble() + ((Number) obj).toDouble()), ((Number) obj).base);
}
}
/**
* This method subtracts two numbers from two different objects
* @param obj the number of the object inputted from user
* @return a new subtracted number object
*/
@Override
public Object subtract(Object obj) throws IllegalArgumentException {
if (!(obj instanceof Number)) {
throw new IllegalArgumentException();
} else if (this.base != ((Number) obj).base) {
throw new IllegalArgumentException();
} else {
return doubleToNumber((this.toDouble() - ((Number)obj).toDouble()), ((Number) obj).base);
}
}
/**
* This method multiplies two numbers from two different objects
* @param obj the number of the object inputted from user
* @return a new multiplied number object
*/
@Override
public Object multiply(Object obj) throws IllegalArgumentException{
if (!(obj instanceof Number)) {
throw new IllegalArgumentException();
} else if (this.base != ((Number) obj).base) {
throw new IllegalArgumentException();
} else {
return doubleToNumber(this.toDouble() * ((Number)obj).toDouble(), ((Number) obj).base);
}
}
/**
* This method divides two numbers from two different objects
* @param obj the number of the object inputted from user
* @return a new divided number object
*/
@Override
public Object divide(Object obj) throws IllegalArgumentException {
if (!(obj instanceof Number)) {
throw new IllegalArgumentException();
} else if (this.base != ((Number) obj).base) {
throw new IllegalArgumentException();
} else if (((Number) obj).toDouble() == 0) {
throw new IllegalArgumentException();
} else {
return doubleToNumber((this.toDouble() / ((Number) obj).toDouble()), ((Number) obj).base);
}
}
}
最后是我的演示类，NumberDemo
public class NumberDemo
{
public static void main(String[] args)
{
Number a = new Number("12.25", 8);
Number b = new Number("13.75", 8);
System.out.println(a.toString() + " + " + b.toString() + " = " +
a.add(b));
a = new Number("ABC.75", 16);
b = new Number("18.5F", 16);
Number c = new Number("2.FB", 16);
System.out.println("(" + a.toString() + " - " + b.toString() + ") / " +
c.toString() + " = " + (a.subtract(b)).divide(c));
a = new Number("3.45", 9);
b = new Number("32.25", 9);
c = new Number("3.05", 9);
System.out.println(a.toString() + "(" + b.toString() + " + " +
c.toString() + " = " + a.multiply(b.add(c)));
a = new Number("10111.11", 2);
b = new Number("1100110.01", 2);
c = new Number("-101", 2);
System.out.println("(" + a.toString() + " - " + b.toString() + ") / " +
c.toString() + " = " + (a.subtract(b)).divide(c));
a = new Number("-5", 8);
b = new Number("5", 8);
System.out.println(a.toString() + " x " + b.toString() + " = " +
a.multiply(b));
a = new Number("-0.5", 8);
b = a;
System.out.println(a.toString() + " x " + b.toString() + " = " +
a.multiply(b));
}
}
当我调用所有算术方法时，它们似乎被调用得很好，但是调用除法会给我带来错误工具提示：
cannot find symbol
symbol: method divide(Number)
location: class Object
我似乎无法找到原因，有人能发现吗？
这是我第一次使用Stockoverflow，所以如果有什么不符合格式规范，请告诉我。