Compilare: user.cpp: In function ‘int main()’: user.cpp:31:26: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(s[i]>='a' && s[i]<='z' || s[i]>='0' && s[i]<='9') ^ user.cpp:36:33: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] while(s[i]>='a' && s[i]<='z' || s[i]>='0' && s[i]<='9') ^