Char String

#include <iostream>

using namespace std;

void convertAllCharacter(char str[])
{
    for (int i = 0; i < strlen(str); i++)
    {
        if (str[i] >= 'A' && str[i] <= 'Z')
        {
            str[i] += 32;
        }
        else if (str[i] >= 'a' || str[i] <= 'z')
        {
            str[i] -= 32;
        }


    }

    cout << str << endl;
}


void convertAllToUpperOrLower(char str[])
{
    unsigned short choose = 0;
    do
    {
        cout << "1 -[lower to upper]\n2 - [upper to lower]\n";
        cin >> choose;

    } while (choose < 1 || choose >> 2);

    switch (choose)
    {
    case 1:

        for (int i = 0; i < strlen(str); i++)
        {
            if (str[i] >= 'a' && str[i] <= 'z')
            {
                str[i] -= 32;
            }
        }

        break;

    case 2:

        for (int i = 0; i < strlen(str); i++)
        {
            if (str[i] >= 'A' && str[i] <= 'Z')
            {
                str[i] += 32;
            }
        }

    default:
        break;
    }

    cout << str << endl;
}

bool isPalindrom(char str[])
{

    for (int i = strlen(str) - 1; i >= 0; i--) {

        if (str[i] != str[(strlen(str) - 1) - i]) {
            return false;
        }
    }


    return true;

}

int main()
{
    char str[20];
    unsigned int choose;

    cout << "Enter value of char string: ";
    cin >> str;

    do
    {

        cout << "Enter value of function:\n[1] lower to upper and upper to lower:\n[2] lower to upper or upper to lower:\n[3] is Palindrom ?\n";
        cin >> choose;

        switch (choose)
        {
        case 1:

            convertAllCharacter(str);

            choose = -1;
            break;

        case 2:

            convertAllToUpperOrLower(str);

            choose = -1;
            break;

        case 3:
            if (isPalindrom(str)) {
                cout << "This char string is palindrom" << endl;
            }
            else {
                cout << "This char string is not palindrom" << endl;
            }
            choose = -1;
            break;
        default:
            break;
        }


    } while (choose < 0 || choose > 6);

}