nkbiti.cpp:1:26: bits/stdc++.h: No such file or directory nkbiti.cpp:4: 'ifstream' is used as a type, but is not defined as a type. nkbiti.cpp:5: 'ofstream' is used as a type, but is not defined as a type. nkbiti.cpp: In function `int main()': nkbiti.cpp:10: `fi' undeclared (first use this function) nkbiti.cpp:10: (Each undeclared identifier is reported only once for each function it appears in.) nkbiti.cpp:21: `fo' undeclared (first use this function)