Compilare: user.c: In function ‘main’: user.c:13:9: warning: implicit declaration of function ‘sqrt’ [-Wimplicit-function-declaration] z=sqrt(x); ^ user.c:13:11: warning: incompatible implicit declaration of built-in function ‘sqrt’ [enabled by default] z=sqrt(x); ^ user.c:7:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmmmc.in","r",stdin); ^ user.c:8:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmmmc.out","w",stdout); ^ user.c:9:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&k); ^ user.c:12:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^