Introduction - If you have any usage issues, please Google them yourself
The integer entered by the user is stored in variable n. Then the while loop is iterated until the test expression n != 0 is evaluated to 0 (false).
After first iteration, the value of n will be 345 and the count is incremented to 1.
After second iteration, the value of n will be 34 and the count is incremented to 2.
After third iteration, the value of n will be 3 and the count is incremented to 3.
After fourth iteration, the value of n will be 0 and the count is incremented to 4.
Then the test expression is evaluated to false and the loop terminates.