This is making no sense to me. I do something to the code and it works only the first time. I then test it again and it goes back to not including the last element in the vector. I have no idea what I am doing wrong. Please help.

cout << "Enter a sentence: " << endl;

getline(cin, sentence);

for (auto x : sentence) // stores individual words in the vector
{
    if (x == ' ')
    {
        myString.push_back(word);
        cout << word << endl;
        word = " ";
    }
    else
    {
        word = word   x;

    }

}
for (auto elem : myString)
{
    cout << elem << endl;
}

CodePudding user response：

If there is no space after the last word, you are not adding it to your vector.

CodePudding user response：

You are scanning the sentence one letter at a time, appending each letter to word until you encounter a space, and only then are you inserting the word into the vector. So, if the sentence does not end with a space, the last word won't be inserted into the vector.

There are a few different ways you can fix that:

1. check if word is not empty after the loop exits, and if not then insert it into the vector:

cout << "Enter a sentence: " << endl;

getline(cin, sentence);

for (auto x : sentence)
{
    if (isspace(static_cast<unsigned char>(x))
    {
        if (!word.empty())
        {
            myString.push_back(word);
            word = "";
        }
    }
    else
    {
        word  = x;
    }
}

if (!word.empty())
{
    myString.push_back(word);
}

for (const auto &elem : myString)
{
    cout << elem << endl;
}

2. Scan for word boundaries yourself, such as with string::find_first_(not_)of():

cout << "Enter a sentence: " << endl;

getline(cin, sentence);

const char* wspace = " \f\n\r\t\v";

size_t start = 0, end;
while ((start = sentence.find_first_not_of(wspace, start)) != string::npos)
{
    end = sentence.find_first_of(wspace, start   1));
    if (end == string::npos)
    {
        myString.push_back(sentence.substr(start));
        break;
    }

    myString.push_back(sentence.substr(start, end-start));
    start = end   1;
}

for (const auto &elem : myString)
{
    cout << elem << endl;
}

3. put the sentence into a std::istringstream and then use operator>> to extract complete whitespace-separate words from it. Let the standard library do all the heavy parsing for you:

cout << "Enter a sentence: " << endl;

getline(cin, sentence);

istringstream iss(sentence);
while (iss >> word)
{
    myString.push_back(word);
}

for (const auto &elem : myString)
{
    cout << elem << endl;
}