Programming

22.1What a program is#

A program is a list of commands that the calculator runs one after another. Use programs to repeat a calculation with new numbers, to ask questions and show results, or to automate steps you do often. A program has a name of up to 8 letters and digits, starting with a letter. Programs are saved with the calculator until you reset it.

22.2Create and run your first program#

Press prgm, move to the NEW tab with ▶ twice, and press enter on Create New. The calculator asks for a name with alpha lock already on, so just press the letter keys, then enter. The program editor opens with a colon at the start of each line. Type a command per line and press enter to start the next line. When you are done press 2ndQUITmode to leave: the program is saved automatically.

To run it, press prgm; the EXEC tab lists your programs. Press the number of the program (this types prgmNAME on the home screen) and then enter to run it. When the program ends the calculator shows Done.

Example 22.1

A program that says hello

1. Press prgm, right, right, enter. Type the name HI: press the keys for H (the ^ key) and I (the x² key). Press enter.

   prgm▶▶enter^x²enter

   

2. Press prgm, right (I/O), 3 to paste Disp, then type "HELLO" using the quote key and letter keys.

   prgm▶3alpha"+alphaH^alphaEsinalphaL)alphaL)alphaO7alpha"+

   

3. Press 2nd mode to leave the editor, then prgm, 1, enter to run HI.

   2ndQUITmodeprgm1enter

22.3Edit, rename and delete programs#

Press prgm, ▶ for the EDIT tab and choose a program to open it again. In the editor ◀ and ▶ move along the line, ▲ and ▼ move between lines, del deletes a character (or an empty line), 2ndINSdel switches insert mode (press enter in insert mode to split a line) and clear empties the current line. A program's text is saved after every key.

22.4The CTL menu: loops, decisions and jumps#

Inside the editor, prgm opens CTL (control) with the I/O and EXEC tabs to its right.

22.5The I/O menu: input and output#

22.6Ask for numbers and show a result#

Example 22.2

Add two numbers

1. Create a program ADD with the lines Prompt A,B and Disp A+B.

   prgm▶▶entermathx⁻¹x⁻¹enterprgm▶2alphaAmath,alphaBappsenterprgm▶3alphaAmath+alphaBappsenter2ndQUITmode

2. Run it and answer 3 and 4.

   prgm1enter3enter4enter

Example 22.3

Input with your own question

1. Create AGE: Input "AGE ",A and Disp A+1.

   prgm▶▶entermathtansinenterprgm▶1alpha"+alphaAmathalphaGtanalphaEsinalpha␣0alpha"+,alphaAmathenterprgm▶3alphaAmath+1enter2ndQUITmode

2. Run it and type 12.

   prgm1enter12enter

22.7Repeat steps with a For loop#

For(I,1,100) runs the lines up to End once for each value of I from 1 to 100.

Example 22.4

Add the numbers 1 to 100

1. Create SUMN: 0→S, For(I,1,100), S+I→S, End, Disp S.

   prgm▶▶enterln5÷logenter0sto→alphaSlnenterprgm4alphaIx²,1,100)enteralphaSln+alphaIx²sto→alphaSlnenterprgm7enterprgm▶3alphaSlnenter2ndQUITmode

   

2. Run it.

   prgm1enter

22.8Make decisions with If, Then and Else#

Example 22.5

Pass or fail

1. Create GRADE: Prompt S; If S≥50; Then; Disp "PASS"; Else; Disp "FAIL"; End. Use 2nd math 4 for ≥.

   prgm▶▶entertan×mathx⁻¹sinenterprgm▶2alphaSlnenterprgm1alphaSln2ndTESTmath450enterprgm2enterprgm▶3alpha"+alphaP8alphaAmathalphaSlnalphaSlnalpha"+enterprgm3enterprgm▶3alpha"+alphaFcosalphaAmathalphaIx²alphaL)alpha"+enterprgm7enter2ndQUITmode

2. Run it and answer 70.

   prgm1enter70enter

Example 22.6

The Else branch

1. Same program GRADE. Run it and answer 30.

   prgm▶▶entertan×mathx⁻¹sinenterprgm▶2alphaSlnenterprgm1alphaSln2ndTESTmath450enterprgm2enterprgm▶3alpha"+alphaP8alphaAmathalphaSlnalphaSlnalpha"+enterprgm3enterprgm▶3alpha"+alphaFcosalphaAmathalphaIx²alphaL)alpha"+enterprgm7enter2ndQUITmodeprgm1enter30enter

22.9Repeat while a condition is true (While)#

Example 22.7

Double until at least 100

1. Create DBL: 1→N, While N<100, 2N→N, End, Disp N.

   prgm▶▶enterx⁻¹apps)enter1sto→alphaNlogenterprgm5alphaNlog2ndTESTmath5100enter2alphaNlogsto→alphaNlogenterprgm7enterprgm▶3alphaNlogenter2ndQUITmode

2. Run it.

   prgm1enter

22.10Jump with Lbl and Goto#

Example 22.8

Count to 10 with a label

1. Create CNT: 0→I, Lbl A, I+1→I, If I<10, Goto A, Disp I.

   prgm▶▶enterprgmlog4enter0sto→alphaIx²enterprgm9alphaAmathenteralphaIx²+1sto→alphaIx²enterprgm1alphaIx²2ndTESTmath510enterprgm0alphaAmathenterprgm▶3alphaIx²enter2ndQUITmode

2. Run it.

   prgm1enter

22.11Show a menu to the user#

Menu( takes a title, then pairs of text and label. When the user picks an option, the program jumps to that label.

Example 22.9

Pick one of two options

1. Create PICK with Menu("PICK","ONE",A,"TWO",B), then Lbl A, Disp "GOT ONE", Stop, Lbl B, Disp "GOT TWO".

   prgm▶▶enter8x²prgm(enterprgmalphaCprgmalpha"+alphaP8alphaIx²alphaCprgmalphaK(alpha"+,alpha"+alphaO7alphaNlogalphaEsinalpha"+,alphaAmath,alpha"+alphaT4alphaW−alphaO7alpha"+,alphaBapps)enterprgm9alphaAmathenterprgm▶3alpha"+alphaGtanalphaO7alphaT4alpha␣0alphaO7alphaNlogalphaEsinalpha"+enterprgmalphaFcosenterprgm9alphaBappsenterprgm▶3alpha"+alphaGtanalphaO7alphaT4alpha␣0alphaT4alphaW−alphaO7alpha"+enter2ndQUITmode

2. Run it. The menu appears. Press 2.

   prgm1enter

   

3. Choose option 2.

   2

22.12Place text on the screen with Output(#

Example 22.10

Write at a row and column

1. Create POS: ClrHome and Output(2,4,"AB").

   prgm▶▶enter87lnenterprgm▶7enterprgm▶52,4,alpha"+alphaAmathalphaBappsalpha"+)enter2ndQUITmode

2. Run it.

   prgm1enter

Example 22.11

Wait with Pause

1. Create WAIT: Disp 1, Pause, Disp 2.

   prgm▶▶enter−mathx²4enterprgm▶31enterprgm8enterprgm▶32enter2ndQUITmode

2. Run it. Only 1 shows. Press enter to continue.

   prgm1enterenter

22.13Call one program from another#

Inside the editor, press prgm, ▶ twice for the EXEC tab and choose a program to paste its call, prgmNAME. When the subprogram ends the calling program continues. Variables are shared between programs. Return leaves a subprogram early and Stop ends everything.

Example 22.12

A main program and a subprogram

1. Create SUB with Disp "B".

   prgm▶▶enterln5appsenterprgm▶3alpha"+alphaBappsalpha"+enter2ndQUITmode

2. Create MAIN: Disp "A", call prgmSUB (EXEC item 2 in alphabetical order), Disp "C".

   prgm▶▶enter÷mathx²logenterprgm▶3alpha"+alphaAmathalpha"+enterprgm▶▶2enterprgm▶3alpha"+alphaCprgmalpha"+enter2ndQUITmode

3. Run MAIN, the first program in the list.

   prgm1enter

22.14Text and strings#

Text between quotes is a string. Strings can be stored in Str1 to Str0 (vars, 7) and joined with +. The CATALOG (2ndCATALOG0) also has sub( (part of a string), length(, inString( (find text), expr( (evaluate text as a calculation) and toString(.

Example 22.13

Join two strings

1. Create JOIN: "AB"→Str1 and Disp Str1+"CD". Paste Str1 with vars, 7, 1.

   prgm▶▶enter,7x²logenteralpha"+alphaAmathalphaBappsalpha"+sto→vars71enterprgm▶3vars71+alpha"+alphaCprgmalphaDx⁻¹alpha"+enter2ndQUITmode

2. Run it.

   prgm1enter

22.15Lists inside programs#

Example 22.14

Build a list of squares

1. Create SQS: seq(X²,X,1,5)→L1 using 2nd stat, right, 5, then Disp L1.

   prgm▶▶enterln9lnenter2ndLISTstat▶5X,T,θ,nx²,X,T,θ,n,1,5)sto→2ndL11enterprgm▶32ndL11enter2ndQUITmode

2. Run it.

   prgm1enter

22.16Stop a running program#

Press on to break a program that is running or waiting, and the calculator shows a BREAK error with a Goto choice that opens the editor at the line. 2ndQUITmode also stops a program with the same BREAK error.

Example 22.15

Break a program

1. Create ASK: Input A. Run it, then press on.

   prgm▶▶entermathln(enterprgm▶1alphaAmathenter2ndQUITmodeprgm1enteron

22.17Read the keyboard with getKey#

getKey gives the code of the last key pressed, or 0 if none was pressed. The code is the key's row times 10 plus its column, counting from the top-left. A common pattern waits for a key: 0→K, Repeat K, getKey→K, End.

Example 22.16

Show the code of a key

1. Create KEY: 0→K, Repeat K, getKey→K, End, Disp K. Use getKey from I/O item 6.

   prgm▶▶enter(sin1enter0sto→alphaK(enterprgm6alphaK(enterprgm▶6sto→alphaK(enterprgm7enterprgm▶3alphaK(enter2ndQUITmode

2. Run it and press the 5 key.

   prgm1enter5