m01.cpp: In function 'int main()': m01.cpp:4: error: 'ifstream' was not declared in this scope m01.cpp:4: error: expected ';' before 'f1' m01.cpp:5: error: 'ofstream' was not declared in this scope m01.cpp:5: error: expected ';' before 'f2' m01.cpp:6: error: 'f1' was not declared in this scope m01.cpp:18: error: 'f2' was not declared in this scope