Hello World

第一篇，写之前沐浴更衣，提笔运气，满头大汗，大笔一挥还是先写个hello world吧。。。LOL

1:  #include <iostream>  
2:  using namespace std;  
3:  int main()  
4:  {  
5:    cout << "Hello world!" << endl;  
6:    return 0;  
7:  }