C Program to Reverse a String

In this article, we will discuss a detailed approach to writing a C program that can reverse a string. This is a fundamental operation in string manipulation and is an important concept in computer science and programming.

A string in C programming is an array of characters ending with a null character (`\0`). For example, the string “hello” can be represented as ‘h’, ‘e’, ‘l’, ‘l’, ‘o’, ‘\0’ in C.

Approach to Reverse a String

There are multiple ways to reverse a string in C. Here, we will discuss two common methods:

1. Using a temporary array
2. Using two pointers

Method 1: Using a Temporary Array

This method involves creating a new temporary array and storing the elements of the original string in reverse order. The following are the steps involved in this approach:

1. Find the length of the original string.
2. Create a new array of the same length.
3. Copy the characters from the original string to the new array, but in reverse order.
4. Append a null character (\0) to the end of the new array.
5. Print the new array.

Here is the C code for this approach:

Method 2: Using Two Pointers

This approach involves using two pointers to swap characters in the original string, which ultimately results in a reversed string. The steps in this approach are:

1. Declare two pointers, start and end.
2. Point start to the beginning of the string and end to the end of the string (excluding the null character).
3. Swap the characters pointed by start and end.
4. Move start one position to the right and end one position to the left.
5. Repeat steps 3-4 until start and end cross each other.

Here is the C code for this approach:

Conclusion

Reversing a string in C programming is a common task that helps to improve your understanding of string manipulation, arrays, and pointers. The two methods discussed here are quite efficient, but the second method is more memory-efficient as it does not require a new array to store the reversed string.