The first line of the covered box reads “if (123 < 10)”. The full block of code in the front box reads as follows:

if (12 < 10)
{
   cout << 12 << end1;
}
else //n is two or more digits long:
{
   writeVertical(12 /10);
   cout << (12 % 10) << end1;
}

The “writeVertical” line is annotated “Computation will stop here until the recursive call returns.”