Compilare: user.cpp: In function ‘int main()’: user.cpp:14:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<=strlen(s);i++){ ^ user.cpp:16:31: warning: left shift count >= width of type [enabled by default] if(s[i]>='A' && s[i]<<'z') ^ user.cpp:17:38: warning: left shift count >= width of type [enabled by default] while(s[i]>='A' && s[i]<<'z'){ ^