Compilare: user.cpp: In function ‘int main()’: user.cpp:12: warning: suggest parentheses around ‘-’ inside ‘<<’ user.cpp:9: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:9: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:30: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result /tmp/ccVDiSJ3.o: In function `main': user.cpp:(.text+0x23c): warning: the `gets' function is dangerous and should not be used.