Eroare de compilare: user.c: In function ‘main’: user.c:9: error: ‘c’ undeclared (first use in this function) user.c:9: error: (Each undeclared identifier is reported only once user.c:9: error: for each function it appears in.) user.c:6: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:7: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result