Im working on a token iterator (valid tokens, "true, false, "true", "&", "!", "(", "false", "^", "true", ")".
The code is working, my question is about return values. I often run into this problem, I have return statements, but the final return statement throws off my result by duplicating the last return statement.
I think I know for sure the error lays within my placement of { and } and while i've learned they aren't necessary, since there's so many nested if's i feel they are necessary.
This seems to be a common problem to me and others ive worked with, does anyone have an idea of how to prevent this problem from happening? Thanks!
My code outputs:
line: [ ! BAD (true ^ false) % truelybad] next token: [!]
next token: [(]
next token: [true]
next token: [^]
next token: [false]
next token: [)]
next token: [)]
and should output
next token: [!]
next token: [(]
next token: [true]
next token: [^]
next token: [false]
next token: [)]
public class TokenIter implements Iterator<String> {
ArrayList<String> token = new ArrayList<String>();
static int count = 0;
// input line to be tokenized
private String line;
// the next Token, null if no next Token
private String nextToken;
// implement
public TokenIter(String line) {
this.line = line;
}
@Override
// implement
public boolean hasNext() {
// System.out.println(count);
return count < line.length();
}
@Override
// implement
public String next() {
while (hasNext()) {
char c = line.charAt(count);
if (c == '!' || c == '!' || c == '^' || c == '(' || c == ')') {
token.add(Character.toString(c));
count++;
nextToken = Character.toString(c);
return nextToken;
} else if (c == 't' || c == 'T') {
count++;
c = line.charAt(count);
if (c == 'r') {
count++;
c = line.charAt(count);
}
if (c == 'u') {
count++;
c = line.charAt(count);
}
if (c == 'e') {
count++;
c = line.charAt(count);
}if (c == ' ' || c == '!' || c == '!' || c == '^' || c == '(' || c == ')'){
token.add("true");
nextToken = "true";
//count++;
return nextToken;
}
} else if (c == 'f' || c == 'F') {
count++;
c = line.charAt(count);
if (c == 'a') {
count++;
c = line.charAt(count);
}
if (c == 'l') {
count++;
c = line.charAt(count);
}
if (c == 's') {
count++;
c = line.charAt(count);
}
if (c == 'e') {
count++;
c = line.charAt(count);
}
if (c == ' ' || c == '!' || c == '!' || c == '^' || c == '(' || c == ')'){
token.add("false");
nextToken = "false";
// count++;
return nextToken;
}
} else if (c == ' ') {
count++;
} else {
count++;
}
}
return nextToken;
}
@Override
// provided, do not change
public void remove() {
// TODO Auto-generated method stub
throw new UnsupportedOperationException();
}
// provided
public static void main(String[] args) {
String line;
// you can play with other inputs on the command line
if (args.length > 0)
line = args[0];
// or do the standard test
else
line = " ! BAD (true ^ false) % truelybad";
System.out.println("line: [" + line + "]");
TokenIter tokIt = new TokenIter(line);
while (tokIt.hasNext())
System.out.println("next token: [" + tokIt.next() + "]");
}
}
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