Compilare: user.c: In function ‘main’: user.c:13:9: warning: variable ‘ok’ set but not used [-Wunused-but-set-variable] int ok; ^~ user.c:11:5: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^~~~~~~~~~~~~~~~~ user.c:12:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("bigfour.out","wt",stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:16:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d%d%d%d",&x,&a,&b,&c,&d); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:50:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("CON","wt",stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~