Facts for Kids

Computers do not speak like people, so we use simple sets of instructions called languages. BASIC is one family of those languages made to be easy for beginners. It uses familiar English words or short abbreviations so students and teachers can tell a computer what to do without hard rules.

BASIC was built so lots of people could try programming, not just experts. Its commands read a bit like plain words, which helps a learner think about steps and results—like saying “give me three apples” to a friend. That friendly style is why BASIC became popular in classrooms.

BASIC is a simple programming language that uses words you already know. The PRINT command shows text on the screen. For example, type: 10 PRINT "Hello, World!" 20 END. END tells the program to stop, but many BASICs do fine without it. If you want the message to repeat forever, use GOTO: 10 PRINT "Hello!" 20 GOTO 10. GOTO 10 tells the computer to jump back to line 10 and do the same thing again.

A clearer way to repeat a set number of times is FOR...NEXT. Use LET to pick how many times: 10 LET N = 3 (this means \(N = 3\), or say hello three times). Then 20 FOR I = 1 TO N 30 PRINT "Hello!" 40 NEXT I. Here \(I\) is the counter that goes from \(1\) to \(N\). You can also use INPUT to ask a friend for a name or how many stars they want, then use a loop to print that many on the screen.

A long time ago, two teachers at Dartmouth wanted every student to use a computer in class, even if they were not science students. They made a simple language that students could learn quickly and run on a shared system so many people could work at once.

They also learned from earlier attempts and from older languages that were harder to read. With extra money and new machines, they released the first easy-to-read version in 1964 so learning to give instructions to a computer became possible for many more people.

Programs use a few basic actions to work with data. LET gives a value to a name (like putting apples in a jar), though many BASICs let you leave LET out and just write the name and value. DATA lists several values that a program can read one by one with READ, and a pointer moves forward each time you READ, so values are used in order.

An array is like a row of small boxes all labeled together; DIM sets up those boxes so you can store many items under one name. If you need to start reading DATA again, RESTORE brings the pointer back to the first value so the program can read the list from the start.

Programs have built-in math helpers. ABS gives the absolute value, which means it drops a minus sign: for example, many BASICs would show that ABS(-3) becomes 3. Another helper, INT, keeps only the whole part of a number so INT(3.7) becomes 3.

SQR finds a square root so SQR(9) is 3. RND gives a random number like 0.2 or 0.9; you can use it to pick things at random. Some versions also had more advanced helpers (like trig or logs) for special math, but ABS, INT, SQR, and RND are the basic tools you meet first.

When we tell a computer something, we store values in a variable—a name that holds a value, like a labeled jar. Early versions let names be very short and handled only whole numbers. Later ones allowed longer names and numbers with decimals, called floating point.

Text is a different kind of value called a string; it is usually wrapped in double quotation marks, for example "hi". Some BASICs add a dollar sign after a name to show it holds text, so name$ would mean the jar holds words instead of numbers.

IF ... THEN ... ELSE is how a program makes a choice. For example, a program can check a number of points (we will call that number score) and do one thing if the score is big and another if it is small. IF checks, THEN does the first action, and ELSE gives the other action if needed.

To do something many times, BASIC used FOR ... TO ... STEP ... NEXT. You set a small counter like count to go from 1 to 3, and the program repeats the steps inside the loop. GOTO jumps to another line, and GOSUB ... RETURN jumps to a short subroutine (like a little helper) and then comes back when you say RETURN. ON ... GOTO/GOSUB picks a jump spot based on a number, like choosing which path to follow.

PRINT shows a message on the screen, for example PRINT "Hello" to say hi. INPUT asks the player to type something, like a name or a number; the program waits until someone types and presses Enter.

You can use LIST to show all the program lines so you can read them. Some BASICs used TAB and SPC to move text across the screen: TAB moves to a column, and SPC adds a few spaces. This helps line things up, for example listing snack counts in neat columns so they are easy to read.

REM means a remark or comment; the computer ignores REM lines and people use them to write notes inside the program. Early BASIC programs often began lines with numbers (like 10, 20, 30) and commands on those lines, for example 10 PRINT "HI". Use LIST to show those lines.

There were also commands like USR or CALL to hand work to a fast machine routine, and TRON/TROFF to turn simple tracing (a way to watch lines run) on and off. Some dialects added one-line functions with DEF FN or special matrix words like MAT, but these details change between versions.