Reversal

2 minutes to read

We are given the following website to write a coding solution:

Reversal 1

Problem

We need to write a program that is able to take a text string and print it in reverse order. For instance:

"asdf" -> "fdsa"

Solution

Since we are allowed to use C, C++, Python and Rust, let’s write a solution on every language, just because.

C

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

int main() {
  // take in the string
  char s[1024] = { 0 };
  fgets(s, sizeof(s), stdin);
  char* newline = NULL;

  if ((newline = strchr(s, '\n'))) {
    *newline = '\0';
  }

  // calculate answer
  char answer[1024] = { 0 };
  int length = strlen(s);

  for (int i = 0; i < length; i++) {
    answer[i] = s[length - i - 1];
  }

  // print answer
  puts(answer);

  return 0;
}

C++

#include <algorithm>
#include <iostream>

int main() {
  // take in the string
  std::string s;
  getline(std::cin, s);

  // calculate answer
  std::string answer = s;
  reverse(answer.begin(), answer.end());

  // print answer
  std::cout << answer << std::endl;

  return 0;
}

Python

# take in the string
s = input()

# calculate answer
answer = s[::-1]

# print answer
print(answer)

Rust

use std::io;

fn main() {
    // take in the string
    let mut input = String::new();

    io::stdin()
        .read_line(&mut input)
        .expect("Failed to read line");

    // calculate answer
    let answer = input.trim().chars().rev().collect::<String>();

    // print answer
    println!("{}", answer);
}

Flag

Using any of these programs, we are able to solve the chalenge and capture the flag:

HTB{r3VerS4l?_wElL_1_n3vEr_d0_th4t_th1ng}