Suppose there is a string and we reverse a string using a pointers in C. Let’s see how is it possible through a pointer. So before proceed we take a little bit of knowledge about pointers here.
Examples:
Input: LingarajTechhub
Output: buhhcdtjaragniL
Input: Qwerty
Ouput: ytrewQApproach:
This approach requires two pointers, one pointing to the beginning of the string and the other pointing to the end of the string. With the help of these two pointers, the characters are then inverted one by one.
Program:
#include <stdio.h>
#include <string.h>
// Function to reverse the string
// using pointers
void reverseString(char* str)
{
int l, i;
char *begin_ptr, *end_ptr, ch;
// Get the length of the string
l = strlen(str);
// Set the begin_ptr and end_ptr
// initially to start of string
begin_ptr = str;
end_ptr = str;
// Move the end_ptr to the last character
for (i = 0; i < l - 1; i++)
end_ptr++;
// Swap the char from start and end
// index using begin_ptr and end_ptr
for (i = 0; i < l / 2; i++) {
// swap character
ch = *end_ptr;
*end_ptr = *begin_ptr;
*begin_ptr = ch;
// update pointers positions
begin_ptr++;
end_ptr--;
}
}
// Driver code
int main()
{
// Get the string
char str[100] = "GeeksForGeeks";
printf("Enter a string: %s\n", str);
// Reverse the string
reverseString(str);
// Print the result
printf("Reverse of the string: %s\n", str);
return 0;
}Output:
Enter a string: LingarajTechhub
Reverse of the string: buhhcdtjaragniL
