Compilare: user.cpp: In function ‘int main()’: user.cpp:19:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] chk[l[i]][r[i]] = chk[r[i]][l[i]] = 1; ^ user.cpp:19:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] chk[l[i]][r[i]] = chk[r[i]][l[i]] = 1; ^ user.cpp:19:35: warning: array subscript has type ‘char’ [-Wchar-subscripts] chk[l[i]][r[i]] = chk[r[i]][l[i]] = 1; ^ user.cpp:19:41: warning: array subscript has type ‘char’ [-Wchar-subscripts] chk[l[i]][r[i]] = chk[r[i]][l[i]] = 1; ^ user.cpp:15:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &n, &m); ^ user.cpp:19:46: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] chk[l[i]][r[i]] = chk[r[i]][l[i]] = 1; ^