Compilare: user.cpp: In function ‘int main()’: user.cpp:42:26: warning: statement has no effect [-Wunused-value] for(i; i<lmax; i++) ^ user.cpp:58:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[i][ch]++; ^ user.cpp:71:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(fr[i][ch]>fr[j][ch]) ^ user.cpp:71:46: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(fr[i][ch]>fr[j][ch]) ^ user.cpp:20:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi, "%d%d", &p, &n); ^