joker.cpp:5: variable `std::ofstream fout' has initializer but incomplete type joker.cpp: In function `int main()': joker.cpp:12: `k2' undeclared (first use this function) joker.cpp:12: (Each undeclared identifier is reported only once for each function it appears in.) joker.cpp:14: `zero' undeclared (first use this function) joker.cpp:19: `sec' undeclared (first use this function) joker.cpp:19: `k3' undeclared (first use this function) joker.cpp: At global scope: joker.cpp:5: storage size of `fout' isn't known