【c++11关键字】 constexpr

/*
 * c++11关键字
 * constexpr
 * 小鱼号的代码日志
*/
#include <QCoreApplication>
#include <iostream>
using namespace  std;
int fact(int n)
{
    return n < 1 ? 1 : (n *fact(n - 1));
}

constexpr int factorial(int n)
{
    return n < 1 ? 1 : (n *fact(n - 1));
}
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    auto n = fact(4);  //运行期计算
    auto m = factorial(6);//编译器计算
    char group[fact(4)];
    char group2[factorial(6)];
    cout << m << "  " << n << endl;
    return a.exec();
}