I used StringTokenizer to get the tokens of a string. But I get two different outputs when I tried to print all the tokens in that StringTokenizer, using a for-loop and a while-loop.
String string="She is an attractive girl, isn't she?";
StringTokenizer stringTokenizer=new StringTokenizer(string,",");
when I tried to print all the tokens using a for loop
for (int i=0;i<stringTokenizer.countTokens();i++)
System.out.println(stringTokenizer.nextToken());
output
She is an attractive girl
when I tried to print all the tokens using a while loop
while (stringTokenizer.hasMoreElements())
System.out.println(stringTokenizer.nextToken());
output
She is an attractive girl
isn't she?
I want to know why the while loop gives the expected two tokens and the for loop doesn't gives the two tokens.
The countTokens() value is decreasing as you call nextToken(). In the first run countTokens() is returning 2 for the two entries found. When you call nextToken() the first time this number is decreased to 1 since there is only one entry left to read. But this means that the for loop will result in
for (int i=0; i<1; i++)
And the for loop variable i is already at value 1. So, since 1<1 is false your for loop terminates without reading the second entry.
You can save the count of tokens in a variable first and then use it in your for loop.
int count = stringTokenizer.countTokens();
for (int i=0; i<count; i++) {
System.out.println(stringTokenizer.nextToken());
}
This way the countTokens() method gets called only once (with the correct value) and not after every nextToken() call with decreasing remaining token count.