Compilare: user.cpp: In function ‘int main()’: user.cpp:13:18: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(c>='a'&&c<='z' || c>='A'&&c<='Z') ^ user.cpp:16:18: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(c>='a'&&c<='z' || c>='A'&&c<='Z') ^ user.cpp:15:11: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(ok==1) ^