#include <iostream>
#include <string>
 
int main()
{
    using std::cout;
    using std::cin;
    using std::getline; //I assume you want spaces in your sentences
    using std::string; // can you use std::string? Or only char arrays/chars?
    using std::endl;
 
 
    string setence , vowels = "";
    int numVowels = 0;
 
    cout << "Please enter a setence: ";
    getline( cin , setence );
 
    for( int i = 0; setence[i]; ++i ) //loop while it is not a null character
    {
        switch( toupper(setence[i]) )
        {
            case 'A': case 'E': case 'I': case 'O': case 'U': //some times y?
            ++numVowels;
            vowels += setence[i];
        }
    }
 
    cout << "Number of vowels: " << numVowels << endl;
    cout << "Vowels used are: " << vowels << endl;
}

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

VGhpcyBpcyBhIHRlc3Qgc3RyaW5nIGJlaW5nIGVudGVyZWQu

This is a test string being entered.