Question

It is possible to delete all characters of a string that is immediately followed by two vowels, without the aid of a char array, using instead exclusively the “string” library ?

For example:

priamo -> iamo

The algorithm should be:

1. Cycling the string making a for loop from 0 to string.length()-2 to prevent overflow
2. Compare pairs of characters with a char array containing all the vowels
3. Using “Erase” function in the string library to delete positions before the vowels

but I have no idea how to implement the second point without the help of an array of characters. Any suggestions?

Answer 1

I’d suggest using std::adjacent_find:

std::string s{"priamo"};
auto is_vowel = [](char c) -> bool {
    static const char vowels[] = "aeiou";
    return std::any_of(std::begin(vowels), std::prev(std::end(vowels)),
        [c](char d) { return c == d; } );
};
auto it = std::adjacent_find(s.crbegin(), s.crend(),
    [&](char c, char d) { return is_vowel(c) && is_vowel(d); }).base();
if (it != s.cbegin())
    s.erase(s.cbegin(), std::prev(it, 2));