Question

I have to write a function that takes a string and returns all the missing letters in the string. The function below seemed simple enough but it’s not returning anything. Any hints?

string getMissingLetters(const string& sentence)
{
    string alphabet = "abcdefghijklmnopqrstuvwxyz";
    string sent = sentence;
    transform(sent.begin(), sent.end(), sent.begin(), ::tolower);

    for(unsigned int i = 0; i < sent.size(); i++)
        for(unsigned int j = 0; j < alphabet.size(); j++)
        {
            if(sent[i] == alphabet[j])
            {
                alphabet.erase(i);
                j--;
            }
        }
    return alphabet;
}

Answer 1

You need

alphabet.erase(j,1);

to erase a single character at position j.