Arrays in for loops

Question

I have an array called blockHeights , which contains 3 values inside of it, namely 1,2,3. So blockHeights[0] is equal to 1.

I also have a loop:

for (int i = 1; i <= blockHeights.length; i++)

In the first time around the loop, I want to create a variable called totalBlockHeights where it is

int totalBlockHeights = blockHeights[0] + blockHeights [1] + blockHeights [2];

However, in the next loop I want that variable to change, so that it only adds blockHeights[1] and blockHeights[2] together, ignoring blockHeights[0] .

How would I go about doing this?

Answer 1

Try the following (I'm assuming the third iteration should only include blockHeights[2] , following the pattern):

for (int i = 1; i <= blockHeights.length; i++) {
    int totalBlockHeights;
    for (int j = i - 1; j < blockHeights.length; j++) { // all block heights from here onwards
        totalBlockHeights += blockHeights[j];
    }
    // do whatever
}

Answer 2

Well, if you want the sum of your array, and the sum of the array without first value

int totalBlockHeights = 0;
for(int i = 0; i < blockHeights.length; i++){
    totalBlockHeights += blockHeights[i];
}

System.out.println(totalBlockHeights);
System.out.println("totalBlockHeights without first value = " + (totalBlockHeights - blockHeights[0]));

this way you only loop once

Answer 3

you can perform this on two for loop outer loop for (int i = 1; i <= blockHeights.length; i++) , and in inner loop (take a variable j) you can do like int totalBlockHeights = totalBlockHeights + blockHeights[j] , and for i<j , you can just continue the for loop.

as answered by btrs20

Answer 4

Try following code:

public class Loop {

    public static void main(String[] argv) {

        int[] blockHeights = new int[] {1, 2, 3};
        int totalBlockHeights = 0;

        for(int i = 0; i < blockHeights.length; i++) {
            totalBlockHeights = 0;
            for(int j = i; j < blockHeights.length; j++) {
                totalBlockHeights += blockHeights[j];
            }
            System.out.println(totalBlockHeights);
        }
    }

}

Answer 5

    int[] blockHeights = new int[] { 1, 2, 3 };
    int totalBlockHeights = 0;
    int customBlockHeights = 0;

    for (int i = 0; i < blockHeights.length; i++) {
        totalBlockHeights += blockHeights[i];
        if (i == 0) {
            continue;
        }
        customBlockHeights += blockHeights[i];
    }
    System.out.println(totalBlockHeights);
    System.out.println(customBlockHeights);

This will print:

6
5

You dont need two for to achieve that.