Java: Hash Function Inputted Strings

Question

I am seeking help creating a hash function that will take user data inputted from a string and convert it into an integer value, all the while skipping white spaces. I am stumped on why it's not working, and how to get it to get white spaces that may be entered and would appreciate the help.

Code:

public static void main(String[] args) {
    Scanner inScan;
    String inStr;
    int outHash;

    inScan = new Scanner(System.in); // Assignment of Scanner

    System.out.print("Enter string to create hash: "); // Asks for String Input
    inStr = inScan.nextLine(); // String Input

    // Start of Hash Function
    String hashValue = inStr;
    hashValue = inStr.hashCode();
    System.out.println(hashValue);

What isn't working? What output are your expecting and what are you getting? What is the exact error message you see? — puhlen, Oct 24 '16 at 20:37
I'm expecting an integer output of some sort depending on whatever the string input is. — Aramza, Oct 24 '16 at 20:37
I believe there is an issue setting up the code to hash out the string. — Aramza, Oct 24 '16 at 20:38
If you are expecting an integer, why is `hashValue` of type `String`? — xiaofeng.li, Oct 24 '16 at 20:39
It should be `int hashValue`. Listen to what the compiler is telling you. — Mick Mnemonic, Oct 24 '16 at 20:40
Changing String hashValue to int hashValue states there's a conversion error. — Aramza, Oct 24 '16 at 20:42
@Aramza You should not need the guess what is wrong here, the error message from your compiler tells you exactly what is wrong. — puhlen, Oct 24 '16 at 20:44
Remove the unnecessary assignment here `String hashValue = inStr;` and instead just do `int hashValue = inStr.hashCode()` — Mick Mnemonic, Oct 24 '16 at 20:44
That still appears to be a conversion, I don't see why it wouldn't work the other way. — Aramza, Oct 24 '16 at 20:45

score 1 · Answer 1 · edited May 23 '17 at 12:33

Your code calls hashCode() on unchanged inStr. You should clear out whitespace from inStr before calling hashCode to make sure hash codes of strings that differ only in white space are identical:

String a = "a bc";
String b = "ab c";
String c = "a b c";
int hashA = a.<remove-white-space>.hashCode();
int hashB = b.<remove-white-space>.hashCode();
int hashC = c.<remove-white-space>.hashCode();

<remove-white-space> is something you need to write. Consult this Q&A for help on this task.

If you do your task correctly, hashA, hashB, and hashC would be equal to each other.

Java: Hash Function Inputted Strings

1 Answers1