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Help with string method

  1. Jun 1, 2007 #1
    Hi. I just started Java and need some help with a method involving strings.

    I need to return the index of the start of the first occurence of one string (parameter two) in another string (parameter one).

    I tried this:
    Code (Text):

    public static int findInString (String text1, String text2)
    int length1 = text1.length();
    int length2 = text2.length();
    int index;
    char x = text2.charAt(0);
    for (index = 0; index < length1; index++)
    char y = text1.charAt(index);
    if (x == y)
    text 1 = text1.substring(index, index + length2);
    if (text1 == text2)
    return index;
    if (index == length1)
    return -1;
    NOTE: I cannot use the indexOf method. It's for a programming class at a local university and he won't let us use it. So I need to find an alternative way to basically do what it does.

    My code compiles; it's just wrong semantically. Any help would be appreciated.
  2. jcsd
  3. Jun 2, 2007 #2


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    Homework Helper

    Search indexes should be limited to length1 - length2, no point in searching past the point where there aren't enough bytes remaining in text1. If length1 < length2, then no match is possible.

    Since this is just a test program, might as well create a string compare function, and then call it to compare &text1[test index], with text2, length of test2, until you get a match or increment test index > (length1-length2).
  4. Jun 2, 2007 #3


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    Science Advisor
    Homework Helper

    I think the basic problem is you are trying to use text1 for two different things. When you assign text1 to a substring of itself, you delete the end of the original string. For example you won't find xyz in abxcdxyz, because you find the first x and then overwrite the long string with xcd.
    Last edited: Jun 2, 2007
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