vc6++不能输出常量？？

Question

#include <iostream>
using namespace std;

int main() {
    std::cout << "Hello World!\n";
    int a='b';
    char c=97;
    cout<<a<<endl;
    cout<<c<<endl;
    cout<<'a'<<endl;
    cout<<"a"<<endl;
    const double PI=3.1415926;
    cout<PI<<endl;
}

不能正常输出最后一个？

Answer 1

cout<PI<<endl;

改为

cout<<PI<<endl;