PE_.idea_misc.xml

<?xml version="1.0" encoding="UTF-8"?>
<project version="4">
  <component name="CMakeWorkspace" PROJECT_DIR="$PROJECT_DIR$" />
</project>

PE_.idea_modules.xml

<?xml version="1.0" encoding="UTF-8"?>
<project version="4">
  <component name="ProjectModuleManager">
    <modules>
      <module fileurl="file://$PROJECT_DIR$/.idea/PE.iml" filepath="$PROJECT_DIR$/.idea/PE.iml" />
    </modules>
  </component>
</project>

PE_.idea_PE.iml

<?xml version="1.0" encoding="UTF-8"?>
<module classpath="CMake" type="CPP_MODULE" version="4" />

PE_CMakeLists.txt

cmake_minimum_required(VERSION 3.8)
project(PE)

set(CMAKE_CXX_STANDARD 17)

set(SOURCE_FILES main.cpp)
add_executable(PE ${SOURCE_FILES})

PE_main.cpp

#include <string> // string
#include <iostream> // cin, cout

using namespace std;

int n;

string wordsArray[10][100];

int longestWord = 0;

int lastFilledIndex[10];

char* map_number(int number) {

    switch (number) {

        case 1:
            return const_cast<char *>("one");

        case 2:
            return const_cast<char *>("two");

        case 3:
            return const_cast<char *>("three");

        case 4:
            return const_cast<char *>("four");

        case 5:
            return const_cast<char *>("five");

        case 6:
            return const_cast<char *>("six");

        case 7:
            return const_cast<char *>("seven");

        case 8:
            return const_cast<char *>("eight");

        case 9:
            return const_cast<char *>("nine");

        case 10:
            return const_cast<char *>("ten");

        default:
            return const_cast<char *>("");
    }
}

int number_char(char *s) {

    return static_cast<string>(s).size();
}

int main() {

    cout << "Enter n of words:\n";

    cin >> n;

    cout << "Enter your words:\n";

    for (int i = 0; i < n; ++i) {

        string s;

        cin >> s;

        if (s.size() > longestWord)
            longestWord = s.size();

        int length = number_char(&s[0]);

        wordsArray[length - 1][lastFilledIndex[length - 1]] = s;

        ++lastFilledIndex[length - 1];
    }

    for (int i = 0; i < longestWord; ++i) {

        cout << map_number(i + 1) << "-letter words\t" << lastFilledIndex[i];

        for (int j = 0; j < lastFilledIndex[i]; ++j)
            cout << "\t" << wordsArray[i][j];

        cout << endl;
    }

    return 0;
}