Given an array of integer.
I want to first print print 1st, 4th, 7th.. numbers. Then 2nd, 5th, 8th.. And then 3rd, 6th, 9th..
I want to use ONLY ONE LOOP to iterate through the array. How can I do this?
(Note: Size of array will always be like 4, 7, 10, 13.. and so on, i.e. in increments of 3.)
Thanks.
Write a function
private int index(int i, int length)
which computes the right index for the loop variable i
EDIT
Wasn't that easy as i first thought:
public static void main(String[] args) {
int[] array = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 };
for (int i = 0; i < array.length; i++) {
System.out.println(array[index(i, array.length)]);
}
}
private static int index(int i, int length) {
int third = (length + 2) / 3;
if (length % 3 == 1 && i >= third) { // spezial, because second third is smaller
return index(i - 1, length - 1);
}
int group = i % third;
return (group) * 3 + (i / third);
}
EDIT did some cleanup;
This is just a rough guess but something like this should work-
int b[]; int temp=b.length;//Store the inputted numbers in this array
for(int i=0, j=0; j<3; i=i+3){
if(i<temp) System.out.println(b[i]);
if(i>=temp){
i=i%3+1;
++j;
}
}
Here's how i would do this,print each array sequence vertically:-
int[] a = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
int k = 3;
for (int i = 0; i < a.length; i += k) {
System.out.print(a[i] + "\t");
if (i + 1 < a.length) {
System.out.print(a[i + 1] + "\t");
if (i + 2 < a.length) {
System.out.println(a[i + 2]);
}
}
}
OUTPUT
1 2 3
4 5 6
7 8 9
10
You need to set the loop index again when length is reached. Check the code below
int a[] = {4,6,7,2,7,8,9,4,3};
int i = 0;
int j = 0;
int start = 3;
int printed = 0;
while (i < a.length && printed < a.length) {
printed++;
System.out.print(a[i] + " ");
i += start;
if (!(i < a.length)) {
i = ++j;
System.out.println();
}
}
Output
4 2 9
6 7 4
7 8 3
Assuming that the length of the array is 9, which is how I read the second line in the question, this would be my approach:
int[] a = {1,2,3,4,5,6,7,8,9};
for (int i = 0; i < a.length*3; i+=3) {
System.out.print(a[i%a.length + i/a.length] + " ");
}
Output:
1 4 7 2 5 8 3 6 9
