CODEWITHSUNDEEP
javaarrays
Kidus Asmare Ayele
Kidus Asmare Ayele

Reputation: 93

How would I allow this to go through every element to check if it is equal?

So I was trying to build a solitaire encryption program, but I keep running into a problem when it comes to this method. The char array a represents the word the user inputs (converted it into an array to make it easier) and the char array b represents the alphabets so it has 25 indexes. What I am trying to do is match the alphabet to its number. It seemed simple enough but I am having a hard time as it keeps throwing an ArrayIndexOutOfBoundsException. I have tried to use for loops, nested for loops and other tests but it keeps throwing the exception or just outputs unexpected results such as [0, 0, 0, 0, 0]. I have debugged it and it seems like b[i] never equals a[j] so j will always be 0.

public static int[] converter(char[] a, char[] b){
    int[] res = new int[a.length];
    int i = 0;
    int j = 0;
    while(i < a.length){
        if(b[i] == Character.toUpperCase(a[j])){ //Does not run through the first loop at all
            res[j] = i + 1;
            j = j + 1;
        } else {
            i = i + 1;
        }
    }
    return res;
}

Please do not link the similar question. It does not answer my question.

Upvotes: 1

Views: 59

Answers (1)

Demomaker
Demomaker

Reputation: 118

The code below is a solution. We want the wordCharacterIndex to iterate through the word to see the place where a character is. The characterIndex iterates through the characters to compare with the word's character present at the wordCharacterIndex. After setting the result, we need to reset the characterIndex so that it goes back to the first character in the character array to compare with the other word characters, if we didn't, the following characters of the word would need to be at a higher character index, which is not what we want. Naming variables actual words is very important to better understand what you are trying to do within your code. You were comparing i < a.length while you were iterating through b[i] which made it possible to go larger than b's bounds and therefore cause an ArrayIndexOutOfBoundsException. I hope this helps you better understand.

public static int[] converter(char[] word, char[] characters){
    int[] result = new int[word.length];
    int characterIndex = 0;
    int wordCharacterIndex = 0;
    while(wordCharacterIndex < word.length){
        if(characters[characterIndex] == Character.toUpperCase(word[wordCharacterIndex])){
            result[wordCharacterIndex] = characterIndex + 1;
            wordCharacterIndex++;
            characterIndex = 0;
        } else {
            characterIndex++;
        }
    }
    return result;
}

Upvotes: 2

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