HA02/src/ArrayManipulation.java

import java.util.Arrays;
public class ArrayManipulation {
  
  public static int[] reverseArray(int[] arr) {
    for (int i = 0; i < arr.length/2; i++) {
      int tmp = arr[i];
      arr[i] = arr[arr.length - 1 - i];
      arr[arr.length - 1 - i] = tmp;
    }
    return arr;
  }
  
  public static int[] removeFirst(int[] arr) {
    if (arr == null || arr.length==0) {
	  int[] result = new int[0];
	  return result;
	}
	if(arr.length == 1||arr.length == 0) {
	  return arr;	  
	}
	int[] result = new int[arr.length-1];
	for(int a=1;a<arr.length;a++) {
	  result[a-1] = arr[a];
	}
    return result;  
  }
  
  public static int[] removeLast(int[] arr) {
    if (arr == null || arr.length==0) {
      int[] result = new int[0];
      return result;
	}		  
	if(arr.length == 1||arr.length == 0) {
	  return arr;	  
	}
	int[] result = new int[arr.length-1];
	for(int a=0;a<arr.length-1;a++) {
	  result[a] = arr[a];
	}
	return result;   
  }
  
  public static int[] squareEach(int[] arr) {
    if (arr == null || arr.length==0) {
	  int[] result = new int[0];
	  return result;
	}
	int[] result = new int[arr.length];
    for(int a=0;a<arr.length;a++) {
	  result[a] = arr[a] * arr[a];
	}
	return result;     
  }
    
  public static void main(String[] args) {   
    int[] arr = {6,7,8,9,10};
    System.out.println(Arrays.toString(reverseArray(arr)));
    System.out.println(Arrays.toString(removeFirst(arr)));
    System.out.println(Arrays.toString(removeLast(arr)));
    System.out.println(Arrays.toString(squareEach(arr)));
  }
}