# Playing with passphrases [6 kyu]

[Playing with passphrases](https://www.codewars.com/kata/559536379512a64472000053)
6 kyu

## Solution

/**
*** Author: R-CO
*** E-Mail: [e-mail]
*** Date: 2020-08-05
**/
#include <algorithm>
#include <cctype>
#include <cstdlib>
#include <iostream>
using std::cout;
using std::endl;
#include <vector>

struct TestCaseStruct {
  struct Input {
    std::string origin;
    int shift;
  } input;
  std::string expected_output;
};

class PlayPass {
 public:
  static std::string playPass(const std::string &s, int n) {
    std::string output = s;

    for (auto &c : output) {
      if (isalpha(c)) {
        c = CircularShift(c, n);
      } else if (isdigit(c)) {
        c = ComplementTo9(c);
      }
    }

		for (size_t index = 0; index < output.size(); index += 2) {
      output[index] = toupper(output[index]);
    }

		for (size_t index = 1; index < output.size(); index += 2) {
      output[index] = tolower(output[index]);
    }

		std::reverse(output.begin(), output.end());

    return output;
  }

 private:
  static char CircularShift(const char c, const int n) {
    char output = c + n;

    if (isupper(c)) {
      if (output > 'Z') {
        output = output - 'Z' + 'A' - 1;
      }
    } else {
      if (output > 'z') {
        output = output - 'z' + 'a' - 1;
      }
    }

    return output;
  }

  static char ComplementTo9(const char c) { return '9' - c + '0'; }
};

int main(int argc, char *argv[]) {
  /*
   */
  TestCaseStruct test_cases[] = {
      {{"I LOVE YOU!!!", 1}, "!!!vPz fWpM J"},
      {{"I LOVE YOU!!!", 0}, "!!!uOy eVoL I"},
      {{"AAABBCCY", 1}, "zDdCcBbB"},
      {{"MY GRANMA CAME FROM NY ON THE 23RD OF APRIL 2015", 2},
       "4897 NkTrC Hq fT67 GjV Pq aP OqTh gOcE CoPcTi aO"}};

  PlayPass solution;
  for (const auto &test_case : test_cases) {
    if (solution.playPass(test_case.input.origin, test_case.input.shift) ==
        test_case.expected_output) {
      cout << "test case \"" << test_case.input.origin.c_str() << "\" is pass."
           << std::endl;
    } else {
      cout << "test case \"" << test_case.input.origin.c_str() << "\" is fail."
           << std::endl;
    }
  }

  return EXIT_SUCCESS;
}

## Result


###### tags: `CodeWars` `C++`