Compilare: user.c: In function ‘add’: user.c:8:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(prim[a] != 0 && i - poz[prim[a]] > d) prim[a] = prev[prim[a]]; ^ user.c:8:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] user.c:8:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] user.c:8:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] user.c:9:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(prim[a] == 0) ult[a] = 0; ^ user.c:9:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] user.c:10:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] len[dr] = len[ult[a]] + 1; ^ user.c:12:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] prev[ult[b]] = dr; ^ user.c:13:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] next[dr] = ult[b]; ^ user.c:14:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] ult[b] = dr; ^ user.c:15:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(prim[b] == 0) prim[b] = dr; ^ user.c:15:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] user.c:20:3: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(next[dr] == 0) prim[b] = dr; ^ user.c: In function ‘main’: user.c:28:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d", &n, &k); ^ user.c:38:10: warning: ‘last’ may be used uninitialized in this function [-Wmaybe-uninitialized] last -= 'a'; ^