I just installed Deepin 23 and write a simple c++ program:

#include 

int main()  {
    std::cout << "Hello Deepin" << std::endl;
}

and I complie it with command

g++ -o test test.cpp

Yet the compiler gives me

/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/11/../../../x86_64-linux-gnu/crt1.o: in function _start': (.text+0x17): undefined reference to main'
collect2: error: ld returned 1 exit status

What's going wrong here?