String Reverse

Reverse the characters in a given string and print the result

Understand the Problem

Problem Statement

A string S is passed as input to the program. The program must reverse the string and print the reversed value.

Constraints

String S contains only printable ASCII characters
String length can vary from 1 to 1000 characters
String may contain spaces, special characters, and alphanumeric characters

Examples

Example 1

Input

abcde

Output

edcba

Explanation

The characters in 'abcde' are reversed to produce 'edcba'

Example 2

Input

abba

Output

abba

Explanation

The string 'abba' is a palindrome, so when reversed it remains the same

Solution

#include <stdio.h>
#include <string.h>

int main() {
    char s[1001];
    fgets(s, sizeof(s), stdin);
    
    // Remove newline character if present
    int len = strlen(s);
    if (s[len-1] == '\n') {
        s[len-1] = '\0';
        len--;
    }
    
    // Print string in reverse
    for (int i = len - 1; i >= 0; i--) {
        printf("%c", s[i]);
    }
    
    return 0;
}

Time:O(n) - We iterate through the string once to print characters in reverse order

Space:O(1) - We only use a constant amount of extra space (excluding the input string storage)

Approach:

The C solution reads the input string using fgets() which safely handles input with spaces. We first remove the trailing newline character if present. Then we iterate through the string from the last character to the first character (len-1 down to 0) and print each character using printf(). This produces the reversed string.

Visual Explanation

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