Compilare: user.cpp: In function ‘int main()’: user.cpp:9:15: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(c>='A' && c<='Z' || c>='a' && c<='z') ^ user.cpp:16:21: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(!(l>='A' && l<='Z' || l>='a' && l<='z')) ^ user.cpp:22:21: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(!(c>='A' && c<='Z' || c>='a' && c<='z')) ^