fib.cpp: In function `int main()': fib.cpp:6: `ifstream' undeclared (first use this function) fib.cpp:6: (Each undeclared identifier is reported only once for each function it appears in.) fib.cpp:6: parse error before `(' token fib.cpp:7: `ofstream' undeclared (first use this function) fib.cpp:14: `fin' undeclared (first use this function) fib.cpp:18: `fout' undeclared (first use this function) fib.cpp:18: `endl' undeclared (first use this function) fib.cpp:11: warning: unused variable `int r'