# Array Reversal in C Hackerrank Solution

## Introduction

In this article, we will delve into the topic of array reversal in C and explore the solution to a popular problem on Hackerrank.

Reversing an array is a common programming task that involves changing the order of elements in an array. We will discuss the approach to solving this problem and provide a step-by-step guide for implementing the solution in C.

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Whether you are a beginner or an experienced programmer, this article will help you understand the concept of array reversal and enhance your coding skills.

## What is Array Reversal?

Before we proceed further, let’s first understand what array reversal means. Array reversal involves rearranging the elements of an array in reverse order.

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The first element becomes the last, the second element becomes the second-to-last, and so on. This process effectively flips the array, changing the order of elements to their reverse positions.

## Array Reversal in C Hackerrank Solution

Now, let’s explore the array reversal solution in C for the Hackerrank problem. The problem statement asks us to reverse the given array and print the reversed array as the output.

We can achieve this using different techniques. In the previous example, we used a swapping technique. Let’s now look at another approach using pointers.

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Here is the step-by-step solution for array reversal in C using pointers:

### Step 1: Input the Array

To begin, we need to input the array elements from the user. The number of elements and their values will vary depending on the problem.

We can use a loop to iterate through the array and prompt the user to enter each element.

#include<stdio.h>

int main() {
int n, i;
printf("Enter the number of elements in the array: ");
scanf("%d", &n);
int arr[n];
printf("Enter the elements of the array:\n");

for(i=0; i<n; i++) {
scanf("%d", &arr[i]);
}

// Array reversal code goes here

return 0;
}

### Step 2: Perform Array Reversal using Pointers

Once we have the array elements, we can proceed with reversing the array using pointers. We will use two pointers, one pointing to the first element and the other pointing to the last element.

Also Read: Median of Two Sorted Arrays in C, C++, Java and Python

By swapping the elements pointed to by these pointers and moving them towards the center of the array, we can reverse the array.

// Array reversal code

int *start = arr;
int *end = arr + n - 1;

while (start < end) {
int temp = *start;
*start = *end;
*end = temp;
start++;
end--;
}

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### Step 3: Print the Reversed Array

Finally, we need to print the reversed array as the output. We can use a loop to iterate through the reversed array and display each element.

printf("Reversed array:\n");
for(i=0; i<n; i++) {
printf("%d ", arr[i]);
}

That’s it! We have successfully reversed the array in C using pointers. The complete code snippet for array reversal in C is as follows:

#include<stdio.h>

int main() {
int n, i;
printf("Enter the number of elements in the array: ");
scanf("%d", &n);
int arr[n];
printf("Enter the elements of the array:\n");

for(i=0; i<n; i++) {
scanf("%d", &arr[i]);
}

int *start = arr;
int *end = arr + n - 1;

while (start < end) {
int temp = *start;
*start = *end;
*end = temp;
start++;
end--;
}

printf("Reversed array:\n");
for(i=0; i<n; i++) {
printf("%d ", arr[i]);
}

return 0;
}

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## FAQs about Array Reversal in C Hackerrank Solution

Here are some frequently asked questions about array reversal in C and its solution for the Hackerrank problem:

1. How does the swapping technique work for array reversal?

The swapping technique used in array reversal involves exchanging the values of two elements. By iterating from the start and end of the array and swapping the elements, we can effectively reverse the array.

2. Can we reverse an array in-place?

Yes, the array reversal solution provided above reverses the array in-place, meaning it modifies the original array without using any additional memory.

3. What is the time complexity of the array reversal solution?

The time complexity of the array reversal solution is O(n), where n is the number of elements in the array. The swapping operation needs to be performed for half of the array’s length.

4. Can we reverse an array using a recursive approach?

Yes, it is possible to reverse an array using a recursive approach. However, the recursive solution may not be as efficient as the iterative solution for large arrays, as it involves multiple function calls.

5. Are there any alternative methods to reverse an array in C?

Yes, there are alternative methods to reverse an array in C, such as using an additional array or using built-in functions like memcpy or memmove. However, the swapping technique and pointer approach provide simple and efficient solutions.

6. How can I practice array reversal and similar problems?

To practice array reversal and similar problems, you can explore coding platforms like Hackerrank, LeetCode, or GeeksforGeeks. These platforms offer a wide range of programming problems to enhance your skills.

## Conclusion

In conclusion, array reversal in C is a fundamental programming concept that involves changing the order of elements in an array.

We discussed two approaches for reversing an array: one using a swapping technique and the other using pointers. Both methods are efficient and allow us to reverse the array in-place.

By understanding and practicing array reversal, you can strengthen your programming skills and tackle similar problems with confidence.