Array Copy And Expand

[jrs362]

One more problem...

I need to write a method(Which i'm calling "expand") that takes an int array as one of its parameters and returns a new int array that is 5 elements longer. The contents of the original array need to be copied into the last elements of the new array. The first 5 elements of the new array need to be set to the value of the second parameter to expand.

So...

int[] a = new int[]{1,2,3,4,5};
int[] a2 = expand(a,-1);

should have the same result as...

int[] a2 = new int[]{-1.-1,-1,-1,-1,1,2,3,4,5};

I currently have:

public void expand(int a[])
{
 
}
 

which approach would be best to use in this situation?

[r035198x]

One more problem...

I need to write a method(Which i'm calling "expand") that takes an int array as one of its parameters and returns a new int array that is 5 elements longer. The contents of the original array need to be copied into the last elements of the new array. The first 5 elements of the new array need to be set to the value of the second parameter to expand.

So...

int[] a = new int[]{1,2,3,4,5};
int[] a2 = expand(a,-1);

should have the same result as...

int[] a2 = new int[]{-1.-1,-1,-1,-1,1,2,3,4,5};

I currently have:

public void expand(int a[])
{
 
}
 

which approach would be best to use in this situation?

1)You need a second parameter for expand and a return type

public int[] expand(int a[], int v) {

2)You want to return an array that is larger than the one you have so you have to declare a new array.The length of this new array is easy: a.length + 5; (So we have)

int[] b = new int[(a.length + 5)];

3)To set the first 5 entries you use a loop

for(int i = 0 ;i < 5;i++) {
    b[i] = v;
}

4) To copy the rest of the array, you start at position 5 in b and at position 5-5 in a.

for(int i = 5 ;i < a.length;i++) {
    b[i] = a[(i - 5)];
}
return b;