Compilare: user.c: In function ‘main’: user.c:10:23: warning: unused variable ‘j’ [-Wunused-variable] long int l,c,x,i,j; ^ user.c:10:21: warning: unused variable ‘i’ [-Wunused-variable] long int l,c,x,i,j; ^ user.c:12:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%ld %ld",&l,&c); ^