#include <QCoreApplication>

#include <iostream>

int main(int argc, char *argv[])

{

    QCoreApplication a(argc, argv);

    std::cout<<("123");

    return a.exec();

}


or

#include <QCoreApplication>

#include <iostream>

using namespace std;

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);

cout << "Hello,World!" << endl;

return a.exec();
}

or

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
double a,b;

cin >> a >> b;
cout << a << "\n";
cout << b << "\n";
cout << sqrt(b) << "\n";//求平方根
cout << "LZH";
return 0;
}

Qt中创建控制台程序（cmd窗口）