The output of the program listed above will be exactly the same as the previous two programs.

At line 10, N is set to equal 1. Line 20 causes the value of N and the square root of N so be printed. At line 30 we sees new type of statement. The "NEXT N" statement causes one to be added to N,

and then if N<=9 we go back to the statement following the "FOR" statement. The overall operation then is the same as with the previous program.

Notice that the variable following the "FOR" is exactly the same as the variable after the "NEXT." There is nothing special about the N in this case. Any variable could be used, as long as it is the same in both the "FOR" and the "NEXT" statements. For instance, "Z1" could be substituted everywhere there is an "N" in the above program and it would function exactly the same.

ANOTHER SQUARE ROOT PROGRAM

Suppose we want to print a table of square roots of each even number from 10 to 20. The following program performs this task:

10 N=10

20 PRINT N;SQR(N)

30 N=N+2

40 IF N<=20 THEN 20

Note the similarity between this program and our "improved" square root program. This program can also be written using the "FOR" loop just introduced.

10 FOR N=10 TO 20 STEP 2

20 PRINT N;SQR(N)

30 NEXT N

Notice that the only major difference between this program and the previous one using "FOR" loops is the addition of the "STEP 2" clause.

This tells BASIC to add 2 to N each time, instead of 1 as in the previous program. If no "STEP" is given in a "FOR" statement, BASIC assumes that 1 is to be added each time. The "STEP" can be followed by any expression.

A COUNT-BACKWARD PROGRAM

Suppose we wanted to count backward from 10 to 1. A program for doing this would be as follows:

10I=10

20PRINT I

30I=I-1

40IF I>=1 THEN 20

Notice that we are now checking to see that I is greater than or equal to the final value. The reason is that we are now counting by a negative number. In the previous examples it was the opposite, so we were checking for a variable less than or equal to the final value.

SOME OTHER LOOPING OPERATIONS

The "STEP" statement previously shown can also be used with negative numbers to accomplish this same result. This can be done using the same format as in the other program:

10 FOR I=10 TO 1 STEP -1

20 PRINT I

30 NEXT I

"FOR" loops can also be "nested." For example:

10 FOR I=1 TO 5

20 FOR J=1 TO 3

30 PRINT I,J

40 NEXT J

50 NEXT I

Notice that "NEXT J" precedes "NEXT I." This is because the J-Ioop is inside the I-loop. The following program is incorrect; run it and see what happens:

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Apple II manual Another Square Root Program, Print Nsqrn Next N, COUNT-BACKWARD Program, Some Other Looping Operations
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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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