如何修复数组越界异常?
我尝试从字符串数组中提取系数和指数。例如:"x^2+2x+1"或"x^5"或"x^2-x+1"。我在这个多项式构造函数中编写的代码适用于大多数情况,但是当字符串的长度为1时,我会得到一个超出界限的索引错误:"EXCEPTION in ThREAD"main"java.lang.ArrayIndexOutOfBibsException:index 1 out out bound for Length 1"。我不确定如何解决这个问题。有人能帮我弄一下这段代码吗?
如果数组的长度为1,我已尝试中断While循环。
public class Polynomial extends PolynomialInterface {
public Polynomial(String s) {
// complete this code
Term newTerm;
DList<Term> dList = new DList<Term>();
int exp = 0;
double coef = 0;
s = s.replaceAll(" ", "");
String[] array = s.split("\+|(?=-)");
for(String i : array){
System.out.println("split: " + i);
}
for (int i = 0; i <= array.length; i++) {
while (array[i].contains("x")) {
exp = 0;
if ((array[i].substring(0, 1).equalsIgnoreCase("x"))) {
coef = 1;
}
if (array[i].substring(0, 1).equals("-") && array[i].substring(1, 2).equalsIgnoreCase("x")) {
coef = -1;
exp = 1;
}
if (array[i].contains("^")) {
int index = array[i].indexOf("^");
String myString = "";
if (index != -1) {
myString = array[i].substring(index + 1, index + 2);
if (!myString.isEmpty()) {
exp = Integer.parseInt(myString);
}
}
}
if (!array[i].contains("^")) {
exp = 1;
}
int end = array[i].indexOf("x");
String subString = "";
if (end != -1) {
subString = array[i].substring(0, end);
if (!subString.isEmpty() && !subString.contains("-")) {
coef = Double.parseDouble(subString);
} else if (!subString.isEmpty() && !subString.equals("-")) {
coef = Double.parseDouble(subString);
}
}
newTerm = new Term(coef, exp);
dList.addLast(newTerm);
if(array.length==1){
break;
}
i++;
}
while (array[i].matches("([-]\d*|\d*)") && (i < array.length)) {
coef = Double.parseDouble(array[i]);
exp = 0;
newTerm = new Term(coef, exp);
dList.addLast(newTerm);
break;
}
}
//super.data = dList;
}
当我调试时,我得到了正确的系数和指数,然后迭代,我得到了一个索引越界错误
解决方案
for (int i = 0; i <= array.length; i++)
您的for循环转到array.long,这会导致空指针异常。 请记住,在Java数组中,从0开始,以array.length-1结束,因此条件应该是 数组长度
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