求高手指点一个c++ 问题

统计元音字母出现的次数
#include<iostream>
using namespace std;

int main()
{
    char ch;
    int aCnt = 0, eCnt = 0, iCnt = 0,
        oCnt = 0, uCnt = 0;

    while(cin >> ch){
        switch(ch){
        case 'A':
        case 'a':
            ++aCnt;
            break;
        case 'E':
        case 'e':
            ++eCnt;
            break;
        case 'I':
        case 'i':
            ++iCnt;
            break;
        case 'O':
        case 'o':
            ++oCnt;
            break;
        case 'U':
        case 'u':
            ++uCnt;
            break;
        }
    }
    cout << "Number of vowel a: \t" << aCnt << '\n'
         << "number of vowel e: \t" << eCnt << '\n'
         << "Number of vowel i: \t" << iCnt << '\n'
         << "Number of vowel o: \t" << oCnt << '\n'
         << "Number of vowel u: \t" << uCnt << endl;

    return 0;
}

如何跳出while循环并执行后面的语句，我已经试过按ctrl+z 但是还是不行 ，请高手指点