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Thread: String Arrays []

  1. #1
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    Default String Arrays []

    Hi guys,

    As part of a Research project in cryptography i am doing a very basic model of a dictionary attack. This is not an actual dictionary attack just to help explain things in my essay.

    So here is what Im trying to do:

    I have made a very small dictionary using String Array that contains just around 50 words or so.
    I have Created Scanner object to read in user input.

    Here is what I have so far:

    String[] words = new String[] { "animal", "anthony", "bear", "bright", 
                "cat", "cities", "control", "copper", "country", "degree", "driving",
                "electric", "earth", "eggs", "expert", "family", "female", "flying",
                "friend", "fuit", "guessing", "german", "gold", "green", "happy", 
                "harbour", "heart", "history", "horse", "insect", "interest", "internet",
                "island", "jelly", "journey", "judge", "kettle", "kiss", "language",
                "laugh", "letter", "loud", "machine", "male", "manager", "market",
                "married", "measure", "monkey", "noise", "nose", "number", "officer",
                "opinion", "other", "orange", "paint", "parcel", "potato", "quick",
                "quiet", "reading", "record", "snow", "school", "science", "ship",
                "teacher", "thunder", "trousers", "value", "voice", "waiting", "walking",
                "woman", "yellow", "zebra"};
     
            // Create a new Scanner Object called scan
            Scanner scan = new Scanner(System.in);
     
            // Print out a request and display to the User
            // & Read In User Input using the Scanner Object
            System.out.println("Enter a common word: ");
            scan.nextLine();

    Right... now what I am trying to do is..... when the user enters a random common word, the program searches the String Array and prints out either ''matching word'' or ''non matching word''.

    So how do i go about getting the program to search the words in the string array.

    I think an if statement is used no ?

    i.e. if ('word entered by user' = 'one of the values in the string array')

    then .....


    Something like that ? But im not really sure.

    Thanks for your help.


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: String Arrays []

    To determine if an item is in an array you will need to look at each element in the array, usually done in a loop.
    You should look at using one of the collection classes to hold the words. Many have a contains() method that will say if an item is in the container. The HashSet class might work

  3. #3
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    Default Re: String Arrays []

    String input = new Scanner(System.in).next(); 
    boolean contains = false;
    for(String w : words){
    if(input.equalsIgnoreCase(w)){
    contains = true;
    break;
    }
    }
    if(contains){
    System.out.println(String.format("Array contains %s", input));
    }else{
    System.out.println(String.format("Array does not contain %s", input));
    }
    If you need to know what index that word is at, just use a normal for loop.

  4. #4
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    Default Re: String Arrays []

    If what you're interested in is an exact match, you can sort your array with Arrays.sort and search it with Arrays.binarySearch. Check the API docs for java.util.Arrays.

  5. #5
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    Default Re: String Arrays []

    Quote Originally Posted by Norm View Post
    To determine if an item is in an array you will need to look at each element in the array, usually done in a loop.
    You should look at using one of the collection classes to hold the words. Many have a contains() method that will say if an item is in the container. The HashSet class might work
    Hi.

    This sounds like the best method.

    So i need to do a if (the string array contains 'the word the user entered')

    then ....... System.out.print("found matching word");

    else ... ("no match found");

    But how do i actually implement this?

    I am really stuck. Please help.

    regards.

  6. #6
    Super Moderator Norm's Avatar
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    Default Re: String Arrays []

    Which technique do you want to use? post#3 shows one way.

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    Default Re: String Arrays []

    Oh Right apologies. I quickly skim read the replies. Didnt realise Post 3 posted code.

    I will now try this.....

  8. #8
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    Default Re: String Arrays []

    Yep that works fine. Just what I wanted.

    thanks alot.

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