Combine two integer arrays into one array in java

Question

I\'ve seen similar questions and none provide the answer that I\'m looking for, so I apologize in advance if this is considered a duplicate. I\'m trying to combine arrays {1

Answer 1

Please try this code, I hope it's useful for you

String a[] = new String[4];
    String b[] = new String[2];
    String[] ab = new String[a.length + b.length];
    int i, j, d, s = 0;
    @SuppressWarnings("resource")
    Scanner x = new Scanner(System.in);
    System.out.println("Enter the first array");

    for (i = 0; i < a.length; i++) {
        a[i] = x.next();
        for (d = i; d < a.length; d++) {
            ab[d] = a[i];
        }
    }

    System.out.println("Enter the second array");

    for (j = 0; j < b.length; j++) {
        b[j] = x.next();
        for (d = a.length + j; d < ab.length; d++)
            ab[d] = b[j];
    }
    System.out.println();
    System.out.println("The new array is !!");
    System.out.println("--------------------");
    for (s = 0; s < ab.length; s++) {
        System.out.print(ab[s] + " ");
    }

Answer 2

One more way of concatenating 2 arrays is:

System.out.println("Enter elements for a: ");
for (int i = 0; i < 5; i++) {
    int num = in.nextInt();
    a[i] = num;
}

System.out.println("Enter elements for b: ");
for (int i = 0; i < 5; i++) {
    int num = in.nextInt();
    b[i] = num;
}

void merge() {
    int c[] = new int[10];
    System.arraycopy(a, 0, c, 0, a.length);
    System.arraycopy(b, 0, c, a.length, b.length);

    System.out.println(Arrays.toString(c));  // merged array 
}

Answer 3

Don't do it yourself, use System.arrayCopy() to copy both arrays into a new array of the combined size. That's much more efficient, as it uses native OS code.

Answer 4

Instead of

int[]c = new int[a+b];

You need to call your merge method and assign the result to the array like :

int[]c = merge(a,b);

Also you for loop should be :

int[]c = merge(a,b);
for(int i=0; i<c.length; i++)
    System.out.print(c[i]+" ");

Answer 5

public static void main(String[]args){

        int[]a = {1, 2, 3};
        int[]b = {4, 5, 6};
        int[]c ;
        c=merge(a,b);
        for(int i=0; i<c.length; i++)
            System.out.print(c[i]+" ");
    }
    public static int[]merge(int[]a, int[]b){
        int[]c = new int[a.length+b.length];
        int i;
        for(i=0; i<a.length; i++)
            c[i] = a[i];
        System.out.println(i);
        for(int j=0; j<b.length; j++)
            c[i++]=b[j];
        return c;
    }

Answer 6

  String a[] = { "A", "E", "I" };
  String b[] = { "O", "U" };
  List list = new ArrayList(Arrays.asList(a));
  list.addAll(Arrays.asList(b));
  Object[] c = list.toArray();
  System.out.println(Arrays.toString(c));