Untitled

Absense of loop rendering code useless?
for (int i = 0; i <= phrase.size(); ++i)
{
    cout << "Character at position " << i << " is: " << phrase[i] << endl;
}

i < phrase.size()  // Given that you are starting from 0th index, I assume
                   // that the valid array indexes are 0 to N-1

for (int i = 0; i < phrase.size(); ++i)
{
    cout << "Character at position " << i << " is: " << phrase[i] << endl;
}

for (int i = 0; i <= phrase.size(); ++i)

for (int i = 0; i < phrase.size(); i++)