Remarks, Relational Tests, Input B, Print NON-ZERO

REMARKS

The REM (short for "remark") statement is used to insert comments or notes into a program. When BASIC encounters a REM statement, the rest of the line is ignored.

This serves mainly as an aid for the programmer and serves no useful function as far as the operation of the program in solving a particular problem.

207 RELATIONAL TESTS

Suppose we wanted to write a program to check whether a number is zero. With the statements we've gone over so far, this could not be done. What is needed is a statement which can be used to conditionally branch to another statement. The "IF-THEN" statement does just that.

Type in the following program: (remember, type NEW first)

10 INPUT B

20 IF B=0 THEN 55

30 PRINT "NON-ZERO"

40 GOTO 10

50 PRINT "ZERO"

60 GOTO 10

When this program is typed and run, it will ask for a value for B. Type in any value you wish. The AIM 65 will then come to the "IF" statement. Between the "IF" and the "THEN" portion

of the statement there are two expressions separated by a "relation."

A relation is one of the following six symbols:

RELATION	MEANING
--------	------------------------
=	EQUAL TO
>	GREATER THAN
<	LESS THAN
<>	NOT EQUAL TO
<= or =<	LESS THAN OR EQUAL TO
=> or >=	GREATER THAN OR EQUAL TO

The IF statement is either true or false, depending upon whether the two expressions satisfy the relation. For example, in the program we just did, if 0 was typed in for B the IF statement would be true because 0=0. In this case, since the number after the THEN is 50, execution of the program would continue at line 50. Therefore, "ZERO" would be printed and then the program would

jump back to line 10 (because of the GOTO statement in line 60).

Suppose a 1 was typed in for B. Since 1=0 is false, the IF statement would be false and the program would continue execution with the next line. Therefore, "NON-ZERO" would be printed and the

GOTO in line 40 would send the program back to line 10.

A PROGRAM USING RELATIONS

Now try the following program for comparing two numbers:

10 INPUT A,B

20 IF A<=B THEN 50

30 PRINT "A IS BIGGER"

40 GOTO 10

50 IF A<B THEN 80

60 PRINT "THEY ARE THE SAME"

70 GOTO 10

80 PRINT "B IS BIGGER"

90 GOTO 10

When this program is run, line 10 will input two numbers from the keyboard. At line 20, if A is greater than B, A<=B will be false. This will cause the next statement to be executed, printing "A IS BIGGER" and then line 40 sends the computer back to line 10 to begin again.

At line 20, if A has the same value as B, A<=B is true so we go to line 50. At line 50, since A has the same value as B, A<B is false; therefore, we go to the following statement and print "THEY

ARE THE SAME." Then line 70 sends us back to the beginning again.

II specifications

The Apple II, launched in April 1977, was one of the first highly successful mass-produced microcomputer products. It marked a significant leap in personal computing, setting standards for future developments in the industry. Created by Steve Wozniak and Steve Jobs, the Apple II differentiated itself with its user-friendly design, appealing aesthetics, and robust capabilities.

One of the standout features of the Apple II was its open architecture, which allowed users to expand and enhance the computer's functionality. This design enabled hundreds of third-party hardware and software developers to contribute to its ecosystem, resulting in an array of peripherals, including printers, modems, and storage devices. The Apple II utilized a MOS Technology 6502 microprocessor running at a clock speed of 1 MHz. Initially equipped with 4 KB of RAM, the machine could be expanded to 48 KB, accommodating more complex applications and programs.

The Apple II was also notable for its colorful graphics. It was one of the first computers to support color display, offering a 6-color palette with a resolution of 280x192 pixels in 16 colors when using its Color Graphics Card. This feature significantly enhanced the visual appeal of games and educational software developed for the platform, making computing more accessible and entertaining for various audiences.

Apple's commitment to user experience was evident in the design of the machine. It featured an integrated keyboard and a plastic case, which was both durable and visually appealing. The self-contained design included drive bays for floppy disk drives, allowing for quicker data access than traditional tape drives. It also supported audio output, enabling sound effects and music, a novelty at the time.

The introduction of the Apple DOS operating system further underscored the machine's capabilities. DOS streamlined file management and made it easier for users to navigate and manage their data. The combination of hardware and software positioned the Apple II as an educational tool and a gaming platform, fostering a vibrant software ecosystem.

The Apple II family continued to evolve, with variations like the Apple II+, IIe, and IIgs being introduced over the years. These iterations brought enhancements in memory, processing power, and graphics capabilities. The legacy of the Apple II endures, not only as a foundational product in personal computing but also as a symbol of innovation that paved the way for future advancements in technology. Its impact is still felt today, as it inspired countless developers and shaped the trajectory of the computer industry.

Apple II Remarks, Relational Tests, Input B, Print NON-ZERO, Print Zero, Less than or Equal to

Models: II