Question

Trying to Solve Euler Problem in which the answer should give a Largest Product of Five consecutive Integers. I got the answer as “40824” which is correct according to Euler solutions. But, i dont understand why does it throw an Exception in the end saying “Exception in thread “main” java.lang.ArrayIndexOutOfBoundsException: 1000
at LargestProduct.main(LargestProduct.java:23)”

Here’s My Code Below:


public class LargestProduct {

static String myBigInteger = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";
static int i;
static int j = 0;
static int BigProduct = 0;

public static void main(String[] args) {

    /* Both methods work to give an integer out of a char*/
    //getNumericValue(c)
    //digit(c,10);

    char[] letters = getStringToArray(myBigInteger);
        for(i=0; i<=letters.length; i++){

                int mydigit1 = Character.digit(letters[i + 0],10);
                int mydigit2 = Character.digit(letters[i + 1],10);
                int mydigit3 = Character.digit(letters[i + 2],10);
                int mydigit4 = Character.digit(letters[i + 3],10);
                int mydigit5 = Character.digit(letters[i + 4],10);

               int newBigProduct = mydigit1 *  mydigit2 * mydigit3 * mydigit4 * mydigit5;

                    if(newBigProduct > BigProduct){
                        BigProduct = newBigProduct;
                    }

                System.out.println("MaxProduct = " + BigProduct);

        }
    }           

public static char[] getStringToArray(String IntegerString) {
    char c[] = IntegerString.toCharArray();
    return c;

}

}

I hope someone can answer this:)
Thanks

Answer 1

One issue I see is:

 for(i=0; i<=letters.length; i++){

should be

 for(i=0; i<letters.length; i++){

index starts from 0, length tells number of elements in array.

Other issue:

            int mydigit2 = Character.digit(letters[i + 1],10);
            int mydigit3 = Character.digit(letters[i + 2],10);
            int mydigit4 = Character.digit(letters[i + 3],10);
            int mydigit5 = Character.digit(letters[i + 4],10);

When you reach max of i, above statements will throw exception.