Processes left-to-right and works safely only when ranges don't overlap.

forward_copy.java

// Forward Copy (left-to-right)
// Suitable when source and destination ranges do NOT overlap,
// or when destination is entirely to the left of source
public static void forwardCopy(int[] arr, int srcStart, int destStart, int length) {
    for (int i = 0; i < length; i++) {
        arr[destStart + i] = arr[srcStart + i];
    }
}

// Example: Copy elements without overlap
// Original: [1, 2, 3, 4, 5]
// Copy indices 1-3 to indices 3-5
// Result:   [1, 2, 3, 2, 3, 4] (indices 3-5 now contain [2, 3, 4])