ferma1.c: In function 'main': ferma1.c:37: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result ferma1.c:38: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result ferma1.c:39: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result ferma1.c:36: warning: 'crez' may be used uninitialized in this function