Answer:
public static void swap(int[] arr, int i, int j) {
if(i >=0 && i <=arr.length-1 && j >=0 && j<=arr.length-1){
int hold = arr[i];
arr[i] = arr[j];
arr[j] = hold;
}
}
public static void allSwap(int[] arr) {
if (arr.length % 2 == 0){
for(int i=0; i<arr.length; i+=2){
int hold = arr[i+1];
arr[i+1] = arr[i];
arr[i] = hold;
}
} else{
System.out.println("array length is not even.");
}
}
Explanation:
The two functions, swap and allSwap are defined methods in a class. The latter swaps the item values at the specified index in an array while the second accepts an array of even length and swap the adjacent values.