Compilare: user.cpp: In function ‘void read()’: user.cpp:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result user.cpp:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:24: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result user.cpp:26: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result user.cpp: In function ‘int eval()’: user.cpp:129: warning: comparison between signed and unsigned integer expressions In file included from /usr/include/stdio.h:910, from user.cpp:1: In function ‘char* gets(char*)’, inlined from ‘void read()’ at user.cpp:24: /usr/include/bits/stdio2.h:230: warning: call to ‘__gets_warn’ declared with attribute warning: please use fgets or getline instead, gets can't specify buffer size In function ‘char* gets(char*)’, inlined from ‘void read()’ at user.cpp:26: /usr/include/bits/stdio2.h:230: warning: call to ‘__gets_warn’ declared with attribute warning: please use fgets or getline instead, gets can't specify buffer size /tmp/cc0g2NCp.o: In function `read()': user.cpp:(.text+0x27e): warning: the `gets' function is dangerous and should not be used. user.cpp:(.text+0x200): warning: the `gets' function is dangerous and should not be used.