Compilare: user.c: In function ‘main’: user.c:7:10: warning: variable ‘a’ set but not used [-Wunused-but-set-variable] char a; ^ user.c:6:24: warning: unused variable ‘j1’ [-Wunused-variable] int i,j,n,m,l,c,i1,j1; ^ user.c:6:21: warning: unused variable ‘i1’ [-Wunused-variable] int i,j,n,m,l,c,i1,j1; ^ user.c:6:19: warning: unused variable ‘c’ [-Wunused-variable] int i,j,n,m,l,c,i1,j1; ^ user.c:6:17: warning: unused variable ‘l’ [-Wunused-variable] int i,j,n,m,l,c,i1,j1; ^ user.c:10:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d" ,&n,&m); ^