Compilare: user.c: In function ‘eval’: user.c:7:5: warning: implicit declaration of function ‘term’ [-Wimplicit-function-declaration] int x=term(); ^ user.c: In function ‘term’: user.c:18:5: warning: implicit declaration of function ‘nr’ [-Wimplicit-function-declaration] int x=nr(); ^ user.c: In function ‘main’: user.c:54:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.in","r",stdin); ^ user.c:55:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.out","w",stdout); ^ user.c:105:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^