public static void displayArray(int array[], int first, int last) {
if (first == last)
System.out.print(array[first] + " ");
else {
int mid = (first + last) / 2;
displayArray(array, first, mid);
displayArray(array, mid + 1, last);
} // end if
}
-Can anyone please explain to me how this method is working. I know that it prints the elements in the array, but I am confused how since there is a no print statement in the recursive case.
Let's say you have an input array like [1, 2, 3, 4, 5],
int[] array = new int[]{1, 2, 3, 4, 5};
displayArray(array, 0, array.length - 1);
Now the functions are called like this way,
displayArray(array, 0, 4) {
int mid = (0 + 4) / 2 = 2;
displayArray(array, 0, 2) { // first, mid
int mid = (0 + 2) / 2 = 1;
displayArray(array, 0, 1) { // first, mid
int mid = (0 + 1) / 2 = 0;
displayArray(array, 0, 0) { // first, mid
System.out.print(array[0] + " ");
}
displayArray(array, 1, 1) { // mid + 1, last
System.out.print(array[1] + " ");
}
}
displayArray(array, 2, 2) { // mid + 1, last
System.out.print(array[2] + " ");
}
}
displayArray(array, 3, 4) { // mid + 1, last
int mid = (3 + 4) / 2 = 3;
displayArray(array, 3, 3) { // first, mid
System.out.print(array[3] + " ");
}
displayArray(array, 4, 4) { // mid + 1, last
System.out.print(array[4] + " ");
}
}
}
array = { 1, 3, 7 }, first = 0, last = 2, then follow the logic and write down what the 2 recursive calls will be. Then for each of those, repeat it.