我正在尝试创建一个表示自然数的不可变类。我使用递归来处理Increment和Decrement方法。由于这些字段是最终的,我做了一个私有构造函数来在递减/递增时将新值赋给必要的字段。在测试这个实现之后,我似乎无法指出问题所在。如果我递减100,那么它将是10.如果我递增99,它将是9.如果我递增/递减一个不在边界上的数字,我会得到一长串乱码。我想我需要向正确的方向推动。如果它是可变的,我可以很好地工作,因为我不必担心最后的字段。制作一个不可改变的类
public final class SlowBigNatural implements BigNatural{
final private int natural[];
final private int nSize;
final private int HIGHEST = 9;
public SlowBigNatural() {
this.nSize = 1;
this.natural = new int[1];
this.natural[0] = 0;
}
public SlowBigNatural(int p) {
this(Integer.toString(p));
}
public SlowBigNatural(String s) {
this.nSize = s.length();
this.natural = new int[nSize];
for (int i = 0; i < nSize; i++) {
this.natural[i] = Character.digit(s.charAt(i), 10);
}
}
public SlowBigNatural(BigNatural c) {
this(c.toString());
}
private SlowBigNatural(int[] natural, int nSize){
this.nSize = nSize - 1;
this.natural = new int[this.nSize];
for (int i = 0; i < this.nSize; i++) {
this.natural[i] = natural[i];
}
}
public BigNatural increment() {
int[] nClone = new int[nSize];
System.arraycopy(natural, 0, nClone, 0, nSize);
if (nSize == 1 || nClone[nSize - 1] != HIGHEST) {
nClone[nSize - 1]++;
BigNatural nInc = new SlowBigNatural(nClone.toString());
return nInc;
}
else {
nClone[nSize - 1] = 0;
BigNatural temp = new SlowBigNatural(nClone, nSize);
temp.increment();
return temp;
}
}
public BigNatural decrement() {
int[] nClone = natural.clone();
if (nClone[nSize - 1] != 0) {
nClone[nSize - 1]--;
BigNatural nDec = new SlowBigNatural(nClone.toString());
return nDec;
}
else {
if (nSize != 1) {
nClone[nSize - 1] = HIGHEST;
BigNatural temp = new SlowBigNatural(nClone, nSize);
temp.decrement();
return temp;
}
else{
BigNatural nDec = new SlowBigNatural(0);
return nDec;
}
}
}
public String toString() {
String nString = "";
for (int i = 0; i < nSize; i++) {
nString += String.valueOf(natural[i]);
}
return nString.replaceFirst("^0+(?!$)", "");
}
}
我跨过我的代码,并且当我将数组转换为字符串并将其传递给构造函数时,似乎发生错误。它将数组变成一堆疯狂。继续调查。
你的代码没有多大意义。例如,为什么在这个语句中,'if(nSize == 1 || nClone [nSize-1]!= HIGHEST)' - 你测试nSize == 1?为什么在接下来的其他章节中,如果你的类被认为是不可变的,你会先执行'temp.increment()'然后返回temp,然后返回'temp.increment()'的结果? –