Strings

// Problem 1
int getCountOfWordsInSentence(const string &sentence) {
    int count = 1;

    for (const char &symbol : sentence) {
        if (std::isspace(symbol))
            count++;
    }

    return count;
}

// Problem 2
int getCountOfSentences(const string &text) {
    int count = 0;

    for (const char &symbol : text) {
        if (symbol == '.')
            count++;
    }

    return count;
}

// Problem 3
void reformatText(string &text) {
    unsigned long long index = 0;

    for (string::iterator i = text.begin(); i < text.end(); ++i, ++index) {
        if (*i == ',')
            text.insert(index + 1, " ");
    }
}

// Problem 4
void deleteMiddleName(string &text) {
    unsigned long long int indexOfFirstPlace = text.find(' ');
    unsigned long long int indexOfLastPlace = text.find(' ', indexOfFirstPlace + 1);

    text = text.erase(indexOfFirstPlace, indexOfLastPlace - indexOfFirstPlace);
}

// Problem 5
bool bothAreSpaces(const char &l, const char &r) {
    return l == ' ' && r == ' ';
}

void removeMultipleSpaces(string &text) {
    string::iterator uniqueIterator = std::unique(text.begin(), text.end(), bothAreSpaces);
    text.erase(uniqueIterator, text.end());
}

// Problem 6
void removeSecondSentence(string &text) {
    unsigned long long indexOfFirstDot = text.find('.');
    unsigned long long indexOfSecondDot = text.find('.', indexOfFirstDot + 1);

    text = text.erase(indexOfFirstDot, indexOfSecondDot - indexOfFirstDot);
}

// Problem 7
char getUpperLetter(const char &letter){
    return static_cast<char>(std::toupper(letter));
}

// Problem 8
void changeLetterCasing(string &text){
    for (char &letter : text){
        if (std::isupper(letter))
            letter = static_cast<char>(tolower(letter));
        else if (std::islower(letter))
            letter = static_cast<char>(toupper(letter));
    }
}