Recursive Character Search and Destroy

I receive a string, and I want to remove any 'a', 'b' and 'c' characters, in a recursive way.

How do I do this in C and Java?

Thanks

char * remove_characters( char * str, char chr )
{
    register char * tmp = str;

    while( * str )
    {
        while( * str == chr )
        {
            str++;
        }

        *tmp++ = * str++;
    }

    * tmp = 0;
    return str;
}