Compilare: user.cpp: In function ‘int sim(int, int)’: user.cpp:30:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] return d[a[i][0]][a[j][0]]; ^ user.cpp:30:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] return d[a[i][0]][a[j][0]]; ^ user.cpp: In function ‘int main()’: user.cpp:47:17: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s1[nr+1]=NULL; ^