Func toUpperCase() and toLowerCase()

#include <iostream>
using namespace std;

char * toUpperCase(char * stroka) {
    char * new_stroka = new char[1];
    for (int i = 0; stroka[i] != 0; i++) {
        if (stroka[i] >= 97 && stroka[i] <= 122) {
            new_stroka[i] = stroka[i] - 32;
        } else {
            new_stroka[i] = stroka[i];
        }
    }

    return new_stroka;
}

char * toLowerCase(char * stroka) {
    char * new_stroka = new char[1];
    for (int i = 0; stroka[i] != 0; i++) {
        if (stroka[i] >= 65 && stroka[i] <= 90) {
            new_stroka[i] = stroka[i] + 32;
        } else {
            new_stroka[i] = stroka[i];
        }
    }

    return new_stroka;
}

int main() {
    char * test_strokaoka = "FatCat";

    cout << test_strokaoka << endl;
    cout << toUpperCase(test_strokaoka) << endl;
    cout << toLowerCase(test_strokaoka) << endl;
    return 0;
}