How to rewrite a nested for loop with a single while loop?

Question

C++ / C#

Greetings!
There is a code snippet in C:

for(int j = 1; j < 3; j++) 
    for(int i = 1; i < j+1; i++)
        printf("%d ", i);

There is a task to rewrite this fragment using only one while loop. I'd like to see different solutions. So far, all that comes to mind is to add conditions to the loop and, at a certain moment, set one of the variables to zero and start counting / output from the beginning.

Answer 1

Well, in general, it comes to your mind correctly, but the option with two cycles, given initially, looks more understandable or something, more readable. Well, only the counters can be renamed (usually i, j, k are used in nested loops in this order - the reverse order is confusing).

int i = 1, j = 1;
do {
  std::cout << j;
  if (++j > i) {
    j = 1;
    i++;
  }
} while (i < 3);

PS: actually, you can still mess around with goto , but this is already too much ...