Sentinel not working? - c++11

Question

I'm not sure why this isn't working, but this is my error message:
Error] no match for 'operator!=' (operand types are 'std::string {aka std::basic_string}' and 'const int')
EDIT: The above issue has been resolved. But, the current issues are redundant ***, and the lack of vowel removal in a sentence rather than just the first word of a sentence.
#include <iostream>
#include <string>
using namespace std;
void removeVowel(string&); // Removes vowels from input string.
string withVowel; // Will be used to read user input.
int main ()
{
const string SENTINEL = "0"; // Sentinel value.
// Request input string unless SENTINEL is entered.
cout << "Enter a word or series of words. " << '\n';
cout << "Or, enter " << SENTINEL << " to quit. " << endl;
cin >> withVowel;
// In case of SENTINEL:
while (withVowel == SENTINEL)
{
cout << "***" << endl;
}
// Run loop.
removeVowel(withVowel);
// Display the string without vowels.
cout << "The word(s) entered reflecting only consonants: " << withVowel << endl;
return 0;
}
void removeVowel(string& withVowel)
{
int i = 0;
int length = int(withVowel.length());
while (i < length)
{
if (withVowel.at(i) == 'a' ||
withVowel.at(i) == 'A' ||
withVowel.at(i) == 'e' ||
withVowel.at(i) == 'E' ||
withVowel.at(i) == 'i' ||
withVowel.at(i) == 'I' ||
withVowel.at(i) == 'o' ||
withVowel.at(i) == 'O' ||
withVowel.at(i) == 'u' ||
withVowel.at(i) == 'U')
{
withVowel.erase(i, 1);
length = int(withVowel.length());
}
else i++;
}
// Display the string without vowels.
cout << removeVowel << endl;
}

Answer 1

Based on your other question, and the error message, I assume withVowel is a std::string. The error message is pretty much telling you what the problem is: you can't compare a std::string with an int.
Since you only need SENTINEL for printing and comparison, just declare it as a std::string as well:
const std::string SENTINEL = "0";

Answer 2

You can't compare const int with strings.
Use ctrl+z and enter to stop the input.
string word;
cout << "ctrl+z and Enter to exit\n";
while (cin >> word){
cout << word << ' ';
// other processing
}
And for your case:
cout << "Enter a word or series of words.\n";
cout << "Ctrl+z and Enter to exit\n";
while (cin >> withVowel){
removeVowel(withVowel);
cout << "The word(s) entered reflecting only consonants :" << withVowel << endl;
}