Compilare: user.cpp: In function ‘int main()’: user.cpp:21:29: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] while(s[i]>='A' && s[i]<='Z' || s[i]>='1' && s[i]<='9') ^ user.cpp:34:29: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] while(s[i]>='a' && s[i]<='z' || s[i]>='1' && s[i]<='9') ^