【求助】类的state成员未定义!
#include <iostream>
using namespace::std;
class foo {
public:
static void print() { cout << sum << endl; }
private:
static double sum;
};
int main()
{
foo x;
x.print();
return 0;
}
#include <iostream>
class foo {
public:
static void print() { std::cout << sum << std::endl; }
private:
static double sum;
};
double foo::sum;
int main(int argc, char* argv[]) {
foo x;
x.print();
return 0;
}