Compilare: main.cpp: In function 'int main()': main.cpp:23:49: warning: array subscript has type 'char' [-Wchar-subscripts] 23 | if (s[i]!=s[i+1] && alfa[s[i]]==0){ | ~~~^ main.cpp:25:33: warning: array subscript has type 'char' [-Wchar-subscripts] 25 | alfa[s[i]]=1; | ~~~^ main.cpp:33:18: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] 33 | s[i]=NULL; | ^~~~ main.cpp:34:18: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] 34 | t[i]=NULL; | ^~~~ main.cpp:37:20: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] 37 | t[i++]=NULL; | ^~~~