int-input.cpp

#include <iostream>
#include <limits>

int main() {
	int input = 0;
	while (1) {
		std::cout << "Enter a number (-1 to quit): ";
		if (!(std::cin >> input)) {
			std::cout << "You entered a non-numeric value..." << std::endl;
			std::cin.clear();
			std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
			continue;
		}
		std::cout << "You entered " << input << '\n';
		if (input == -1) break;
	}
}