Compilare: user.cpp: In function ‘int main()’: user.cpp:23:45: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(i=0;i<n;++i) ++freq[s[i]]; ^ user.cpp:36:44: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(s[i]!=s1[i]) if(a[s[i]]==0 || a[s[i]]==s1[i]) a[s[i]]=s1[i]; else u=1; ^ user.cpp:36:58: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(s[i]!=s1[i]) if(a[s[i]]==0 || a[s[i]]==s1[i]) a[s[i]]=s1[i]; else u=1; ^ user.cpp:36:74: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(s[i]!=s1[i]) if(a[s[i]]==0 || a[s[i]]==s1[i]) a[s[i]]=s1[i]; else u=1; ^ user.cpp:36:21: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(s[i]!=s1[i]) if(a[s[i]]==0 || a[s[i]]==s1[i]) a[s[i]]=s1[i]; else u=1; ^