int something1, something2, something3;
std::cin >> something1 >> something2 >> something3;
// if you are
// using namespace std;
// you can drop the std:: at the beginning of std::cin
There are two separate issues here. One is how you write the code. The other is how the user types the input.
For example you could do this:
1 2 3 4
int a, b, c;
cin >> a;
cin >> b;
cin >> c;
The user may enter the data like this: 1
2
3
or 1 2 3
Alternatively you could put:
1 2
int a, b, c;
cin >> a >> b >> c;
and the user may again respond with either: 1
2
3
or 1 2 3
That's because the >> extraction operator normally ignores whitespace, including space, tab and newline characters.