java - combine two sorted arrays

Question

I want to combine two sorted arrays, so they just need to be compared and printed out. The problem I have is, that the output is wrong, because the programm just goes through the second for-loop. What do I have to do to make it work?

result = {1,2,3,3,3,5,5,6,7,8,9,9,10}

    public static void main(String[] args) {

        int[] array1 = { 1, 3, 3, 5, 6, 9 };
        int[] array2 = { 2, 3, 5, 7, 8, 9, 10 };
        int i;
        int j;
        int a;
        int b;

        for (j = 0; j < array1.length; j++) {
            a = array1[j];
            for (i = 0; i < array2.length; i++) {
                b = array2[i];
                if (a < b) {
                    System.out.print(a);
                } else if (b < a) {
                    System.out.print(b);
                } else if (a == b) {
                    System.out.print(a + b);
                }
            }    
        }    
    }   
}

You are using the same index variable _i_ for the both the **for-loop** — Praveen, Nov 20 '17 at 14:39
*I want to combine two sorted arrays, so they just need to be compared and printed out* I can't understand what that mean. Combining and comparing look like completely different things to me. Elaborate, with a concrete example. — JB Nizet, Nov 20 '17 at 14:40
Duplication of [https://stackoverflow.com/questions/5958169/how-to-merge-two-sorted-arrays-into-a-sorted-array](https://stackoverflow.com/questions/5958169/how-to-merge-two-sorted-arrays-into-a-sorted-array) — Törpetestű, Nov 20 '17 at 14:41
@Praveen I noticed it, but it doesn't change the problem. It keeps looping the second array over and over and does not compare it to the first one — JacobBalb, Nov 20 '17 at 14:41
what do you want to do? Compare first element of array1 with first element of array2, second with second and so on? What appen if array haven't same number of elements? — Francesco Serra, Nov 20 '17 at 14:43
@JBNizet I added the result it should print out in this example — JacobBalb, Nov 20 '17 at 15:00
Learn to use the StackOverflow search engine. The URL is "www.google.com". — DwB, Nov 20 '17 at 16:13
Do what? **adding** numbers is not the same as **merging** arrays — OneCricketeer, Nov 20 '17 at 16:25

ajc · Answer 1 · 2017-11-20T16:10:34.057

0

algo --

int i=0, j=0, k=0
int[] result = new int[arr1.length+arr2.length];
while (i<arr1.length && j<arr2.length)  {
    if(arr1[i] <= arr2[j]) {
        result[k++] = arr1[i++];
        // or if u just want to print do a sysout. 
    } else {
        result[k++] = arr2[j++];
    }
} 

while(i<arr1.length) 
     result[k++] = arr1[i++];

while(j<arr2.length) 
     result[k++] = arr2[j++];

edited Nov 20 '17 at 16:10

answered Nov 20 '17 at 15:03

ajc

1,685
14
34

java - combine two sorted arrays

1 Answers1