Compilare: user.cpp: In function ‘int main()’: user.cpp:26: warning: comparison between signed and unsigned integer expressions user.cpp:21: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:22: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:23: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result user.cpp:24: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result /tmp/ccDFzG0M.o: In function `main': user.cpp:(.text+0x144): warning: the `gets' function is dangerous and should not be used.