c++ statement what it says

new will allocate requested memory to a pointer variable/object.

int* n=new int[5]; 

will allocate 5 integer bytes of memory to pointer n (5 * 4 = 20 bytes will be allocated, considering int size is 4 bytes in the system).
sizeof will return memory size of the given data type.

int s=sizeof(int); 

On executing this line, s will have value 4, considering int size is 4 bytes in the system).

On your code, "node" should be a structure or a class. "new1" is the pointer of type "node". You are allocating 1 object memory and creating object for "node". Allocated memory address will be stored in "new1" pointer. But, if sizeof(node) returns 20, 20 * sizeof(node) bytes will be allocated to new1 object.

new1=new node[sizeof(node)]; 

Note that you need to call

delete[] new1;

at end to deallocate the memory you consumed for new1.

Ok, I will try to explain.

First, this seems to be coded by someone who does not really understand the concepts of new and delete, and is rather used to malloc and free.

Second, apparently, new1 is, or should be a variable of type node*. If it is not, then probably the whole line doesn't do what the author intended.

Third, the expression allocates and initializes an array of (sizeof(node)) elements of type node. The initialization happens by calling the constructor node::node() of every element. If you ask me, the sizeof(node) part is a remnant of a former malloc command, and, in fact a mistake, as indicated above.