how is cin and cout working in the below program?

the below program

#include <iostream>
using namespace std;

int main()
{
    char ch;
    while (cin >> ch){
        cout << ch; 
    }
   return 0;
}

input : abcEnter
output : abc

Whatever I type on the keyboard gets printed only when I press Enter i.e. new line.

Why is not each character being printed simultaneously? Which statement here takes the newline as an input and prints all the characters printed till now?