comb.cpp: In function `int main()': comb.cpp:5: `ifstream' undeclared (first use this function) comb.cpp:5: (Each undeclared identifier is reported only once for each function it appears in.) comb.cpp:5: parse error before `(' token comb.cpp:6: `ofstream' undeclared (first use this function) comb.cpp:7: `f' undeclared (first use this function) comb.cpp:19: `g' undeclared (first use this function)