Radio Shack TRS-80 PC-3 User Manual

lines can make a program hard to read and modify, however, so it is good programming practice to use them only where the state-
ments are very simple or there is some special reason to want the statements on one line.
Also
in this program we have used the FO R verb on line 120 and the N EXT verb on line 150 to create a loop. In Example 3, you
created an "infinite" loop which kept repeating the statements inside the loop until you pressed the ~ key. With this FOR/
NEXT loop, the PC-3 adds 1 to N each time execution reaches the NEXT verb. It then tests to see if N is larger than the limit L.
If N is less than or equal to L, execution returns to the top of the loop and the statements are executed again. If N is greater than
L, execution continues with the 160 and the program stops.
You may use any numeric variable in a FO R/N EXT loop. You also do not have to start counting at 1 and you can add any amount
at each step. See Chapter 8 for details.
We have labelled this program with line numbers starting with 100. Labelling programs with different line numbers allows you to
have several programs in memory at one time. To RUN this program instead of the one at line 10 enter:
RUN 100
In addition to executing different programs by giving their starting line number, you can give programs a letter name and start
them with the DEF key (see Chapter 6).
You will
notice that while the program is running, the BUSY indicator is lit at those times that there is nothing on the display.
RUN
the program a few more times and try setting N at several different values.
Storing Programs in the PC-3's Memory
You will remember that settings, ReSerVe keys, and functions remain in the computer even after it is turned OFF. Programs
also remain
in memory when you turn off the PC-3, or it undergoes an AUTO OFF. Even if you use the ~ ,CLear or CA
70

Radio Shack TRS-80 PC-3 Specifications

General

Brand	Radio Shack
Model	TRS-80 PC-3
Category	Calculator
Language	English