Compilare: user.cpp: In function ‘int main()’: user.cpp:19:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] s2[n2]=s[i]; ^ user.cpp:26:20: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(s2[i]=='a') ^ user.cpp:35:28: warning: array subscript has type ‘char’ [-Wchar-subscripts] s3[n3]=s2[i]; ^ user.cpp:42:20: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(s3[i]=='a') ^ user.cpp:51:28: warning: array subscript has type ‘char’ [-Wchar-subscripts] s2[n2]=s3[i]; ^ user.cpp:58:20: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(s2[i]=='b') ^ user.cpp:67:28: warning: array subscript has type ‘char’ [-Wchar-subscripts] s3[n3]=s2[i]; ^