using namespace std;
int main(void)
{
string str1 = "C++ is ";
string str2 = "Cool! and funny!";
string str3;
str3 = str1 + str2; // 문자열 결합 연산
cout << str3 << endl;
str1 += str2; // 문자열 추가 연산
cout << str1;
return 0;
}