Compilare: user.cpp: In function ‘int f()’: user.cpp:8: warning: no return statement in function returning non-void user.cpp: In function ‘int main()’: user.cpp:20: warning: comparison between signed and unsigned integer expressions user.cpp:20: warning: comparison between signed and unsigned integer expressions user.cpp:22: warning: comparison between signed and unsigned integer expressions user.cpp:28: warning: comparison between signed and unsigned integer expressions user.cpp:35: warning: comparison between signed and unsigned integer expressions user.cpp:10: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:11: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:18: warning: ‘end’ may be used uninitialized in this function