Compile Error: Cannot Find Symbol
I am receiving the error cannot find symbol when the code reaches the recursive call for increment and I have no idea why? Here is the code for increment. Any help will be greatly appreciated.
public void increment() {
Integer first = 0;
Character ch = num.charAt(num.length()-1);
Integer last = Character.digit(ch, 10);
if (num.length() > 1)
{
if (last == 9) {
last = 0;
if (num.length() >= 2)
{
String temp = new String(num.substring(0, num.length()-2));
temp.increment();
}
else
{
last++;
}
}
}
else
{
if (last == 9)
{
last = 0;
first = 1;
}
else
{
last++;
}
}
String t = new String();
String x = new String();
t = last.toString();
x = first.toString();
if (first > 0)
{
num.concat(x);
}
num.concat(t);
}
EDIT: I'm really new to java so the more basic you can make your answers, the better. Ok so the error I am receiving is: BigNatural.java.35: cannot find symbol symbol method increment() location: class java.lang.String temp.increment()
And to clear up any other issues here is the whole code.
public class BigNatural {
private String num;
public BigNatural(String input) {
num = input;
}
public BigNatural(BigNatural input) {
num = input.toString();
}
pub开发者_StackOverflowlic BigNatural(Integer input) {
num = input.toString();
}
public BigNatural() {
Integer i = 0;
num = i.toString();
}
public void increment() {
Integer first = 0;
Character ch = num.charAt(num.length()-1);
Integer last = Character.digit(ch, 10);
if (num.length() > 1)
{
if (last == 9) {
last = 0;
if (num.length() >= 2)
{
String temp = new String(num.substring(0, num.length()-2));
temp.increment();
}
else
{
last++;
}
}
}
else
{
if (last == 9)
{
last = 0;
first = 1;
}
else
{
last++;
}
}
String t = new String();
String x = new String();
t = last.toString();
x = first.toString();
if (first > 0)
{
num.concat(x);
}
num.concat(t);
}
public void decrement() {
Character ch = num.charAt(num.length()-1);
Integer last = Character.digit(ch, 10);
if(num.length() > 1)
{
if(last == 0)
{
String temp = new String(num.substring(0, num.length()-2));
temp.decrement();
}
else
{
last--;
}
}
else
{
if(last > 0)
{
last--;
}
else
{
last = 0;
}
}
String t = new String();
t = last.toString();
num.concat(t);
}
public String toString() {
return num;
}
} public class BigNatural {
private String num;
public BigNatural(String input) {
num = input;
}
public BigNatural(BigNatural input) {
num = input.toString();
}
public BigNatural(Integer input) {
num = input.toString();
}
public BigNatural() {
Integer i = 0;
num = i.toString();
}
public void increment() {
Integer first = 0;
Character ch = num.charAt(num.length()-1);
Integer last = Character.digit(ch, 10);
if (num.length() > 1)
{
if (last < 9) {
last++
}
else
{
last = 0;
if (num.length() >= 2)
{
String temp = new String(num.substring(0, num.length()-2));
temp.increment();
}
}
else {
last++;
}
}
else
{
if (last == 9)
{
last = 0;
first = 1;
}
else
{
last++;
}
}
String t = new String();
String x = new String();
t = last.toString();
x = first.toString();
if (first > 0)
{
num.concat(x);
}
num.concat(t);
}
public void decrement() {
Character ch = num.charAt(num.length()-1);
Integer last = Character.digit(ch, 10);
if(num.length() > 1)
{
if(last == 0)
{
String temp = new String(num.substring(0, num.length()-2));
temp.decrement();
}
else
{
last--;
}
}
else
{
if(last > 0)
{
last--;
}
else
{
last = 0;
}
}
String t = new String();
t = last.toString();
num.concat(t);
}
public String toString() {
return num;
}
}
String has no method called increment. And of course it isn't a recursive call because you are inside an object(which object? in your code there isn't a class definition) , meanwhile you are invoking increment upon a String object.
In addition your temp field is never used. If you want to share it between method calls you can try something like this:
public void increment (String temp){}
and then pass it while calling it:
String temp = new String(num.substring(0, num.length()-2));
increment(temp);
Of course your function can't work like that. temp parameter should be managed inside your increment method. Review your logic. It's no more a matter of syntax. If you can't change the method signature then declare temp as a field of your BigNatural class:
public class BigNatural {
private String num;
private String temp
......
and inside increment method simply do:
temp = new String(num.substring(0, num.length()-2));
Some other pointers:
String is an immutable class meaning once it is created it can no longer be changed. So, doing
String t = new String();
t = last.toString();
has now sense since you will create 2 String Objects here (last.toString()
will create and return a new String).
Simply do:
String t = last.toString();
or even better:
num.concat(last.toString());
Same goes for temp String, simply do:
String temp = num.substring(0, num.length()-2);
Next, be aware of unintentional autoboxing:
Integer first = 0;
first++;
this will create a new Integer Object every time first++
is executed; Integer (as String) is immutable.
When calculating simply use the primitive int
instead of Integer
.
Finally, be careful that you don't create an infinite loop. If I understand your code num will concatenated to so num.length() > 1
will be true always if it was true the first time.
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