+1

1

-1

-1

6523

6523

-23.460

-23.46

1E20

1E+20

-12.3456E-7

-1.23456E-06

1.234567E-10

1.23457E-10

1000000000

1E+09

999999999

999999999

.1

.1

.01

.01

.000123

1.23 E-04

A number input from the keyboard or a numeric constant used in a BASIC program may have as many digits as desired, up to the maximum length of a line (72 characters) or maximum numeric value. However, only the first 10 digits are significant, and tenth digit is rounded up.

PRINT 1.23456789876543210 1.2345679

206 VARIABLES

ASSIGNING VARIABLES WITH AN INPUT STATEMENT

Following is an example of a program that reads a value from the keyboard and uses that value to calculate and print a result:

10 INPUT R

20 PRINT 3.14159*R*R

RUN ?10 314.159

Here's what's happening: When BASIC encounters the input statement, it outputs a question mark

(?)on the display and then waits for you to type in a number. When you do (in the above example, 10 was typed), execution continues with the next statement in the program after the variable (R) has been set (in this case to 10). In the above example, line 20 would now be executed. When the formula after the PRINT statement is evaluated, the value 10 is substituted for the variable R each time R appears in the formula. Therefore, the formula becomes 3.14159*10*10, or 314.159.

If we wanted so calculate the area of various circles, we could rerun the program for each successive circle. But, there's an easier way to do it simply by adding another line to the program, as follows:

30 GOTO 10 RUN

?10

314.159

?3

28.27431

?4.7

69.3977231

?

By putting a "GOTO" statement on the end of our program, we have caused it to go back to line 10 after it prints each answer for the successive circles. This could have gone on indefinitely, but we decided to stop after calculating the area for three circles. This was accomplished by typing a carriage return to the input statement (thus a blank line).

VARIABLE NAMES

The letter "R" in the program above is a "variable." A variable name can be any alphabetic character and may be followed by any alphanumeric character (letters A to Z, numbers 0 to 9).

Any alphanumeric characters after the first two are ignored.

Here are some examples of legal and illegal variable names:

Legal Illegal

A % (first character must be alphabetic)

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Apple II manual Variables Assigning Variables with AN Input Statement, Input R, Variable Names
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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.
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