Counting number of special characters in a given String

Question

I'm trying to make a program that will count the special characters in a given string. But it is not working. Here's my code.

public static final String []specialChars = {"!", "@", "#", "$", "%", "^", "&", "*", "(", ")",
                                             "[", "]", "|", ";", "'", ",", ".", "/", "{", "}", 
                                             "\\", ":", "\"", "<", ">", "?" };

I used array because i'm trying to trace the matched special character in a String. So I decided to do the loop.

int specialCharCount = 0;
        for ( int x = 0; x < specialChars.length ; ++x) {
               specialCharCount = password.length() - password.replaceAll("\\specialChars[x]", "").length();
           }
           System.out.print(" and " + specialCharCount + " special characters.\n\n");

It is running but it gives me this output:

and 0 special characters.

Peter Lawrey · Accepted Answer · 2015-01-10T10:45:34.527

1

The problem you have is that you only consider the number of the last character. I suspect you want the sum of all the special character counts.

for( int x = 0; x < specialChars.length ; ++x) {
    specialCharCount += password.length() 
                    - password.replaceAll("\\" + specialChars[x], "").length();
}

BTW stepping through your code in you debugger would have found that pretty quickly.

How about.

String SPECIAL_CHARS_REGEX = "[!@#$%^&*()\\[\\]|;',./{}\\\\:\"<>?]";

int specials = password.split(SPECIAL_CHARS_REGEX, -1).length - 1;

edited Jan 10 '15 at 10:45

answered Jan 10 '15 at 10:22

Peter Lawrey

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when I add `+` it's still zero. When I used the `SPECIAL_CHARS_REGEX` the output turn to `-1` my sample input is `@#%` – Yodism Jan 10 '15 at 10:30
@Patrick it wasn't counting any trailing special characters, fixed now http://ideone.com/GBWtzf – Peter Lawrey Jan 10 '15 at 10:45
I knew it I lost the `-1` in a parameter. What is the used of `-1` there btw? – Yodism Jan 10 '15 at 10:50

score 1 · Answer 2 · answered Jan 10 '15 at 10:29

1

There are few issues in the code that I see

+= - I think you want to increase the count every time. Having = in the code will assign the count of the last special character in your string ("?")
password.replaceAll() will not modify the original string. String in java are immutable. you will have to assign the return referce to itself again.

password = password.replaceAll("REPLACING STRING", "REPLACED BY STRING");
The first parameter in the following code should not be password.replaceAll("\\specialChars[x]", "") within quotes. In your case it is taken as string literal rather than the actual value of the specialChars[x].

There is a difference between "specialChars[x]" and specialChars[x]

answered Jan 10 '15 at 10:29

Keen Sage

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Thank you Sir. I based my `replaceAll` here to count the number of special character. [link](http://stackoverflow.com/questions/11573939/how-to-count-special-character-in-a-string) – Yodism Jan 10 '15 at 10:34
That is fine. but the next time it goes into the loop your password will still have the initial value instead of the replaced value. So the password.length() will always be same for the entire loop. You might want to check you logic. – Keen Sage Jan 10 '15 at 10:40

Counting number of special characters in a given String

2 Answers2