Compilare: user.c: In function ‘main’: user.c:16:7: warning: variable ‘_ret’ set but not used [-Wunused-but-set-variable] int _ret; ^ user.c: In function ‘solve’: user.c:105:11: warning: unused variable ‘x’ [-Wunused-variable] int j,k,x; ^ user.c: In function ‘main’: user.c:31:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d",a+i); ^ user.c:41:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d",&_b); ^