2

I just started programming java, and I'm new to English please try to understand my sentence.

I tried to add a fifth number inside the the array. The for loop is not reading number 99 inside the array. I don't want table.length then add one , i want to add as many number as i want in the array and without change the for loop. Is there a code to find how many numbers are in a box(the first array box)?

    int[][] table = { { 12, 0, 0, 0 ,99}, { 0, 0, 0, 0, 99}, { 0, 0, 0, 0, 99} };
    int max = Integer.MIN_VALUE;

    for (int i = 0; i < table.length; i++) {
        for (int k = 0; k <= table.length; k++) {
            if (table[i][k] >= max) {
                max = table[i][k];
            }
        }
    }
    System.out.println(max);

    int min = Integer.MAX_VALUE;

    for (int i = 0; i < table.length; i++) {
        for (int k = 0; k <= table.length; k++) {
            if (table[i][k] <= min) {
                min = table[i][k];
            }
        }
    }
    System.out.println(min);
Improve this question

2 Answers 2

Reset to default
5

Hello and welcome to the fun world of Java :-D

The problem is that your "inner" arrays have length 5, but the outer array is of length 3. You are re-using table.length for both loops. For the inner loop try

    for (int k = 0; k < table[i].length; k++) { // Iterate across all the inner arrays
        if (table[i][k] >= max) {
            max = table[i][k];
        }
    }

You are also iterating the table twice, once to find the max value and once to find the min. This is not too expensive with only a few elements, but imagine if you had millions. You can combine both checks in one pass of table. You can also reduce the amount of code by setting a variable for the value in the table. It means you only need to access the array once. Not much of a saving CPU wise, but it makes the code a little easier on the eye.

int[][] table = { { 12, 0, 0, 0 ,99}, { 0, 0, 0, 0, 99}, { 0, 0, 0, 0, 99} };
int max = Integer.MIN_VALUE;
int min = Integer.MAX_VALUE;

for (int i = 0; i < table.length; i++) {
    for (int k = 0; k < table[i].length; k++) {
        int val = table[i][k];
        if (val > max) {
            max = val;
        }
        if (val < min) {
            min = val;
        }
    }
}
System.out.println(max);
System.out.println(min);
Improve this answer
Sign up to request clarification or add additional context in comments.

Comments

2

What Spangen has mentioned is absolutely right with a small correction that you should iterate within "inner" arrays with "<" rather then "<=" which will break the array index.

for (int k = 0; k < table[i].length; k++) { // Iterate across all the inner array
    if (table[i][k] >= max) {
        max = table[i][k];
    }
}

If you are trying to learn array in general than this if fine, else there are better ways to do this in Java 8 as mentioned here Finding minimum and maximum in Java 2D array

Improve this answer

Comments

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.