Compilare: user.cpp: In function ‘int main()’: user.cpp:20: warning: NULL used in arithmetic 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:13: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result /tmp/cc1PxeS6.o: In function `main': user.cpp:(.text+0x7a): warning: the `gets' function is dangerous and should not be used.