Compilare: user.c: In function ‘parseint’: user.c:7:5: warning: implicit declaration of function ‘isdigit’ [-Wimplicit-function-declaration] while (isdigit((c = getchar()))) ^ user.c: In function ‘main’: user.c:14:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("adunare.in","r",stdin); ^ user.c:15:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("adunare.out","w",stdout); ^