Compilare: user.c: In function ‘main’: user.c:24: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:25: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:27: warning: ignoring return value of ‘gets’, declared with attribute warn_unused_result user.c:28: warning: ignoring return value of ‘gets’, declared with attribute warn_unused_result /tmp/cc0gcvh2.o: In function `main': user.c:(.text+0xd6): warning: the `gets' function is dangerous and should not be used.