Compilare: user.c: In function ‘main’: user.c:11: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:12: warning: ignoring return value of ‘gets’, declared with attribute warn_unused_result user.c:29: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:32: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result /tmp/ccETRCvy.o: In function `main': user.c:(.text+0x3f): warning: the `gets' function is dangerous and should not be used.