Step 1:  Concentrate on reading and checking the arguments
   Step 1A:  Make sure there are two
   Step 1B:  Make sure both are integers (perhaps by using strtol)
   Step 1C:  Get them in the right order
   Step 1D:  Make sure that confirm to three rules in the assignment
      (1) there are exactly two distinct arguments
      (2) both of the arguments are valid positive integers
      (3) the smaller number divides into the larger one
      (4) the larger number is less than 1,000,000
   About half the effort of writing the assignment will be here.
   Be sure to test your program on all the test cases given in
   the assignment before proceding to Step 2.

Step 2:
   Do steps 2 and 3 in a C functions with a prototype similar to:
     void PrintTable(int n, int m) 
   Expect this function to be about 20 lines long.

   I'm suggesting that you store the numbers that you will be using
   in the count into an array.  You can avoid the array, but
   it will make step 3 more complicated.

   Find the numbers that divide into the larger but not the smaller.
   Store these into an array.
   I'm not sure how large the array needs to be, but a program
   I've written suggests that 240 should be big enough for
   numbers up to 1,000,000.

   Print the numbers in the array to see if they look correct
   before going on.  Do not go to Step 3 until your number look good!

Step 3:
   Using a doubly nested loop, print the table.