Java if-statement being skipped

Question

The method below takes in a string and a pattern and returns true if they match each other. A '.' matches 1 char and a '*' matches 0 or more (e.g. expMatch("abc", "a.c") should return true). I added a bunch of print statements to see where I went wrong and it seems like the if statement is being skipped even if the str.length() == 1.

I call it with System.out.println(expMatch("abc", "a*c"));

Here is the code:

public static boolean expMatch(String str, String pat)
{   
    if (str.charAt(0) == pat.charAt(0) || pat.charAt(0) == '.')
    {
        System.out.println("in if");
        System.out.println(str.charAt(0));
        System.out.println(pat.charAt(0));
        System.out.println(str.length());
        if (str.length() == 1)
            return true;
        expMatch(str.substring(1), pat.substring(1));
    }

    else if (pat.charAt(0) == '*')
    {   
        System.out.println("in else");
        System.out.println(str.charAt(0));
        System.out.println(pat.charAt(0));
        if (str.length() == 1)
            return true;
        if (str.charAt(0) == pat.charAt(1)) //val of * = 0
            expMatch(str, pat.substring(1));
        else if (str.charAt(1) ==pat.charAt(1))
            expMatch(str.substring(1), pat.substring(1));           
    }

    return false;           
}

and the output is:

in if
a
a
3
in else
b
*
in if
c
c
1
false

Even if the length is 1 it skips the if? Any idea why? P.S. I'm not looking for the solution, just why the if statement is being skipped.

Answer 1

You always return false from the method at the very end. You are calling expmatch recursively but never using the return value. The code comes in to the first if, recurses (because length is not 1) and upon returning will go to the final return statement which returns false.