HP HP12C hp 12c_user's guide_English_E_HDPMBF12E44.pdf - Page 104

104 Section 9: Branching and Looping Looping If a i instruction specifies a lower-numbered line in program memory, the instructions in the program lines between the specified line and the i instruction will be executed repeatedly. As can be seen in the illustration above under Simple Branching, once the program begins executing the "loop" it will execute it again and again. If you want to terminate the execution of a loop, you can include an o or m instruction (described below) or an t instruction within the loop. You can also terminate execution by pressing any key while the loop is being executed. Example: The following program automatically amortizes the payments on a home mortgage without requiring you to press f! for each payment. It will amortize one month's payments each time or one year's payments each time the loop is executed, depending on whether the number 1 or 12 is in the display when you start running the program. Before running the program, we'll "initialize" it by storing the required data in the financial registers - just as we would do if we were amortizing a single payment manually. We'll run the program for a $50,000 mortgage at 123/4% for 30 years, and we'll key 1 into the display just before running it in order to amortize monthly payments. For the first two "passes" through the loop we'll execute the program one line at a time, using Ç, so that we can see the looping occurring; then we'll use t to execute the entire loop a third time before terminating execution. Keystrokes fs fCLEARÎ ?0 Display 00- 00- 01- 44 Sets calculator to Program mode. Clears program memory 0 Stores the number from the display into register R0. This number will be the number of payments to be amortized. File name: hp 12c_user's guide_English_HDPMBF12E44 Printered Date: 2005/7/29 Page: 104 of 209 Dimension: 14.8 cm x 21 cm