Reversing an Array

Implementation of 2 of the methods which can be used to reverse an array.

Reversing Techniques :

  • Reversing using Auxiliary Array
  • Reversing by Swapping Elements

Reversing Using Auxiliary Array :

In this method, we create a new array which stores the values of the input array in reverse order and then overwrites the input array with newly created array.
void reverseByCopy(int a[], int n) {
​
int i, j, b[n]; // New array to store in reverse order
// Storing elements in 'b' array in reverse order
for (i = n-1, j = 0; i >= 0; i--, j++) {
b[j] = a[i];
}
// Overwriting 'a' array
for(int i = 0; i < n; i++) {
a[i] = b[i];
}
}

Reversing by Swapping Elements :

In this method, we keep swapping the left side and right side elements of the array until all the elements are swapped.
void reverseBySwap(int a[], int n) {
​
int i, j;
// i is set to left end, j is set to right end
for (i = 0, j = n-1; i < j; i++, j--) {
int temp = a[i];
a[i] = a[j];
a[j] = temp;
}
}
Contributed by Nitin Ranganath