下面這程式碼按下Ctrl+z結束while輸入後，接下來的cin >> val2就無法輸入了

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <typeinfo>

using namespace std;

int main()
{
	vector<int> vi;
	int val;
	while (cin >> val)
		vi.push_back(val);
	int val2;
	cout << "Please enter the integers that you want to seek:" << endl;
	cin >> val2;
	cout << "The sequence contains " << (count(vi.cbegin(), vi.cend(), val2)) << " " << val2 << endl;

	return 0;
}
 

必須在結束while後加一條cin.clear()才能正常執行（注意：要先按回車，再按ctrl+z，因為ctrl+z位於行首才表示結束輸入，否則只會被當成一個字元來處理，Ctrl+z的ASCII碼是26）

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <typeinfo>

using namespace std;

int main()
{
	vector<int> vi;
	int val;
	while (cin >> val)
		vi.push_back(val);
	int val2;
	cin.clear();
	cout << "Please enter the integers that you want to seek:" << endl;
	cin >> val2;
	cout << "The sequence contains " << (count(vi.cbegin(), vi.cend(), val2)) << " " << val2 << endl;

	return 0;
}