Top 10k strings from Interactive BASIC Programming (1985)(Eigen Software)(Tape 1 of 3 Side B).tzx in <root> / bin / z80 / software / Sinclair Spectrum Collection TOSEC.exe / Sinclair ZX Spectrum - Utilities & Educational / Sinclair ZX Spectrum - Utilities & Educational - [TZX] (TOSEC-v2007-01-01) /
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6 ;"Press any key to continue":
3 statements.
3 statement.
3 Run the program found in this Learning Element.
3 Run the program found in this Learning Element
2 yourname=632.1
2 circumference=2
2 RANDOMIZE USR
2 ;"toggle sound: SPACE & ENTER"
2 ;"help: CAPS SHIFT & ENTER";
2 ;"has a circumference of ";circumference;
2 ;"forward: SYMBOL SHIFT & SPACE";
2 ;"backward: SYMBOL SHIFT & ENTER";
2 ;"and an area of ";area
2 ;"WARNING: if you enter
2 ;"Loading, please wait!"
2 ;"Interactive BASIC Programming";
2 ;"Copyright
2 ;"A circle of radius ";radius;
2 80,75 then
2 , it must be followed by
2 "Please enter radius ";radius
2 the Solution, then
2 1985 Eigen Software"
2 EIGEN SOFTWARE";
2 create reality"
1 x, y, s and t
1 x (where x
1 total=total+anumber
1 statement
1 refer to the same box, as far asyour Spectrum is concerned.
1 r. The areaof a circle equals
1 r,c;x;",";y
1 prints 36. Both
1 module d
1 module c
1 just to see what happens!
1 it could easily have been:
1 give an arc on the other side ofthe imaginary line. Run the program found in this Learning Element.
1 facilities encounter-ed so far.
1 ensure circle is not "rubbed out"
1 d$="Tuesday"
1 d$;" ";day;" ";m$;" ";year
1 count=count+1
1 c=d*c 130
1 c=6 110
1 are not allowed.
1 a=(4+8)^(9-7)
1 You might want to look at this program when you've learnt more about Basic.
1 What you might not have realisedthough is that each character square is made up of 8 rows and 8 columns of dots! Computer people call these dots pixels (picture elements). Hence each character square contains 8*8 = 64 pixels.
1 Try one line per bar
1 This is a bit long winded. We can place several statements on one line if we separate each one with a colon :
1 Silly menu driven program
1 Set up axes
1 Print the name of a town
1 Print square root
1 Plot a cross
1 Play a tune
1 More circle data
1 Make the border red
1 MODULE D &?
1 MODULE C
1 LeonardCohen
1 If you have any suggestions for 'Advanced Interactive BASIC Programming' then Eigen Software would be grateful to hear them. Thankyou
1 Green Sleeves
1 GOTO 220
1 Draw a circle
1 Don't worry about this program, just run it.
1 Don't worry about this program, just run it.
1 Don't worry about this program, just run it!
1 Date again
1 Created with Ramsoft MakeTZX
1 Circle data
1 ;option;" not available!":
1 ;count;" numbers so far.";
1 ;.... then
1 ;"y-coordinate no good, try again!":
1 ;"x-coordinate no good, try again!":
1 ;"x first";
1 ;"entering 1, 2, 3 or 4"
1 ;"The square root of ";number;
1 ;"The date is ";Day;"/";Month;"/";Year
1 ;"The circle is too big to draw!"
1 ;"That's too hard, try again:":
1 ;"Straight lines to begin with.
1 ;"Select option by";
1 ;"Running total is ";total
1 ;"Press any key to end"
1 ;"Portree"
1 ;"Now for a curve.
1 ;"Learning Module D"
1 ;"Learning Module C"
1 ;"4 Make the border red"
1 ;"3 Draw a circle";
1 ;"255,90";
1 ;"2 Play a tune";
1 ;"166,93";
1 ;"166,137"
1 ;"140,120"
1 ;"1 Print the name of a town";
1 ;", then y"
1 ;" ";
1 ;" "
1 55,0 gives a horizontal line because there is no change in the y-coordinate. ";
1 54,0 gives a horizontal line to the right.";
1 40,30 draws a line from 100,90 to 100+40,90+30 (i.e. to 140,120)"
1 255,90 then
1 25,20 then
1 166,93 then
1 125,85 120
1 120,16
1 110,20 gives";
1 100,90 gives:"
1 0,44 gives a vertical line upwards.";
1 0,-78 gives a vertical line downwards.";
1 0,-66 gives a vertical line because there is no change in the x-coordinate. "
1 /6 radians.
1 .02,33 150
1 . What would you expect
1 . Thenwrite a program that inputs three numbers for today's date and prints it in the form 5/6/59
1 . Temporary colour items can be used too.
1 . So you now have a way for repeating BASIC. Use
1 . Negative values of
1 . If y then clear the screen (using
1 . If the condition is true then the instructions are carried out. If the condition is false then the Spectrum ignores the instructions and goes on to the next line. Let's see what is meant by a condition. First take a look at the following relations:
1 . Forsmaller arcs
1 . The modified
1 . Then it draws a straight line from the old plot position to the new plot position i.e. from
1 . The string that does not containany characters at all ("") is called the empty string. (N.B. " " is not the empty string since it contains the character whose code is 32.)
1 . Please note that
1 . Experiment for a while with
1 .
1 -33,0 gives a horizontal line to the left.";
1 , multiply it by itself
1 , centred at
1 , hence a semi-circle is
1 , add one to it and replace it in the same box.
1 , i.e. all
1 ,
1 ,
1 ,
1 ) for the name of a string variable e.g.
1 ) for each circle.
1 ) at the end of the name of a string variable.
1 ) a string. The following are examples of strings:
1 (i.e. 768 character positions).
1 (You will have to press CAPS SHIFT and BREAK {just BREAK} tostop the program.)
1 "y-coordinate please? (0-175) ";y
1 "x-coordinate please? (0-255) ";x
1 "c=";c;"d=";d;"e=";e
1 "Year? ";year
1 "Please give me a number"
1 "Month? ";m$
1 "First we'll use a
1 "First plot a pixel, this gives us a sensible point to start.
1 "Enter a number please ";number
1 "Day of the week? ";d$
1 "Day of the month? ";day
1 "August 1914"
1 "Arcs from larger circles";
1 "Another pixel? (y/n) ";a$
1 "Another number? (y/n) ";a$
1 "All manner of curves!"
1 "Ahhh. That's better....."
1 would print 144 since 4+8=12 and 9-7=2 so (4+8)^(9-7) is the same as 12^2 = 144. Write a program that asks for a radius and prints the circumference and area of the corresponding circle. (Spectrum contains
1 will print 8Try it.
1 will print
1 will draw a circle of radius
1 variablename
1 variable=
1 to the ink colour. You can also use the temporary colour items
1 to draw a smile (with teeth!).
1 to do? Try it.
1 to calculatea new plot position, say
1 the start).
1 the begining of the program. (In fact the first line of your program could be
1 tells the Spectrum to add
1 tells the computer to cease execution of the program.) Write a short program that uses a simple menu like: 1 Print the name of a town 2 Play a tune 3 Draw a circle 4 Make the border red
1 statementse.g.
1 statements. Write a programthat draws a multi-coloured kiteor a plant or a dinosaur or a tin of custard powder!
1 statements. Try
1 statements,each one following a suitable
1 statements to make up your own zaps.
1 statements after the
1 statements but are printed on the input line! Enter
1 statements e.g.
1 statement:
1 statement. Write a program that plots a small crossin the centre of the screen.
1 statement. Print a message if the circle is too big.
1 statement tells your Spectrum to stop executing the current sequence of instructionsand continue from the specified line of the program.
1 statement may be useful.
1 statement lets us place lines and curves on the screen and
1 statement it produces aflashing cursor and expects you to type in a number. Run this program:
1 statement is used to place dots on the screen, i.eit changes a pixel to the ink colour. The
1 statement in a way similar to the
1 statement for repetition.
1 statement for repetition.
1 statement draws anarc (not a circle) from
1 statement to give the answer, e.g.
1 statement and uses this position as a starting point for the
1 so on receiving y you would just have to
1 set the plot position to 0,0
1 semitones above (below if
1 semi-circle. Exampleswill make this clear (continue).
1 seconds at apitch of
1 radius<=87
1 radius
1 radiansand 30
1 radians correspond to 360
1 program continues below
1 now exists inyour Spectrum and it contains the number you entered. To provethis, enter
1 mybankbalance=30000000
1 moves the pitch up or down by octaves. Try entering
1 means raise to the powerof. So
1 means jump (or go to) line
1 means is not equal to. So the following conditions are true:
1 means find the square root of what follows. So
1 means take what is present in variable
1 lie inside the range 0-255 and
1 lie inside the range 0-175.
1 less than
1 is used for circles - easy isn't it!
1 is the vertical coordin- ate (0-175)] will change the pixel at
1 is the same as
1 is the same as
1 is the horizontal coordinate (0-255) and
1 is negative) middle C. (Refer to the first diagram in Chapter 19 of your Spectrum Handbook {HOW TO MAKE MUSIC AND SOUND EFFECTS in Chapter 2}). One octave is represented as: C C# D E
1 is another way of giving (assigning) a number to a variable. When your Spectrum executes (carries out) an
1 is a full circle. The Spectrum uses anoth-er measure of angle: radians. 2
1 is a positive or negative number) isused to put the number x into a box called
1 is a modification of
1 is measured in radians.
1 into it. Now write a program that inputs appropriate information and prints the current date in the form: Saturday 8 September 1984
1 have higher precedence than
1 give anarc on the right hand side of the imaginary straight line from
1 from the last
1 draws asemi-circle from
1 draws a semicircle on the opposite side to the
1 d=c+7 120
1 corresponds to a right angle whereas 360
1 circumference=2*
1 causes Spectrum's loudspeaker (quietspeaker!) to make a sound for a duration of
1 can take any values(positive or negative) as long as the resulting
1 can range from -60 to 69. Write a program that plays a simple tune of your choice.
1 because the square root of 25 is 5 and 5*6=30. You can use brackets to evaluate something more complicated. So
1 as before) through an angle
1 are legal variableswhereas
1 are carried out before
1 and place the answer back in the variable
1 a number"
1 You will need to write something like
1 You will need to use an
1 You will need to input two strings and two numbers.
1 You will need four
1 You can place several statements on one BASIC line. This is done by placing a colon (:) between each statement. e.g.
1 You can have statements like
1 You can draw successive lines or arcs with several
1 Write a program that draws x- and y- axes for a graph and label them accordingly.
1 Write a program that draws several concentric circles.
1 Write a program that draws a picture of your own design.
1 Write a program that acceptsa number as input and prints itssquare root with a suitable message.
1 Write a program that combines
1 Work out the total number of pixels (dots) on the Spectrumscreen.
1 Why not try writing a program that prints the perimeter and area of a rectangle and then draws the rectangle, given its length and breadth?
1 When you've learnt more BASIC. We'll show you how to write a program for sketching colour pictures. Meanwhile, write a program that uses all the
1 We'll have a listen to some sound now.
1 We will now look at an extremely important part of BASIC:
1 We cannot use all of the 49152 pixels because the bottom two rows are reserved for input.We can draw, however, on a grid that is 176 pixels high (22 rowseach 8 pixels high) and 256 pixels wide (32*8).
1 Wait a minute! Let's look atyour last program (the one that draws circles). If you were to enter a radius greater than 87 the circle would go off the screen and your Spectrum would produce the "out of screen" error message. If you place the centre of the circle in the middle of the screen (127,87) the largest circle you can draw has a radius of 87. Enter a larger radius in your program, just to see what happens!
1 Use three different variables.
1 Use three
1 Use the same centre (i.e the same values of
1 Use something like
1 Use several
1 Use four separate
1 Use different values of
1 Try plotting these coordinates:
1 This is an example of an
1 This Learning Module is all about drawing lines, curves and circles. Also some sound. The Spectrum screen is made up of 24 rows and 32 columns. So there are 24*32=768 squares intowhich you can put a letter, digit, symbol etc.
1 There is one restriction: you can only use a single letter(plus
1 Then experiment with
1 Then enter a number. The variable
1 The pitch values for a
1 The names given to variablescan be of any length but can only be made up of letters and digits and they must start with a letter (phew!).
1 The circumference of a circle is equal to 2
1 The Spectrum remembers
1 The Spectrum expects us to refer to each pixel using a coordinate system. Don't worry, coordinates are really quite easy to understand. Honestly! Look at the screen layout given in Chapter 15 of the Spectrum Manual {last page}. x-coordinates start at the bottom left corner of the screen with the value 0 and increase from left to right up to the value 255. In a similar way the y-coordinates start at 0in the bottom left corner of thescreen (ignoring rows 22 and 23)and increase from bottom to top up to the value 175.
1 Text (and colour items) can be placed in
1 THEN CIRCLE
1 String variables are boxes that are quite different from numerical variables and you must tell your Spectrum which you are using! This is done by placing a dollar symbol (
1 So far we have used specificnumbers and text. However, your Spectrum really comes into its own when we use numbers and textthat change. Such changeable things are called variables. We will deal with numeric variablesfirst. Think of a numeric variable as abox set aside in the Specrtum's memory. This box can contain only numbers. Because we might want to use several "boxes" at once we need to refer to them separately. So, each box is given a name by the programmer. In fact the very act of using the name creates the variable (or box). However, do not try toget a number out of a box if youhave not already put one in!
1 Run the program found in this Learning Element.
1 Remember to use short durations.
1 Remember that after a
1 Positive values of
1 Notice line 180 of the lastprogram. It contained
1 Modify your program so that it draws a circle with the correct radius as well as printing the circumference and area.
1 Modify your program so it puts up the prompt: Another number? (y/n). If the response is n then
1 Like numeric variables, string variables are created by using them!
1 Let's have a look at two of the functions available on your Spectrum:
1 Let's consider angular measure. We are used to measuring angles in degrees so that 90
1 In order to produce zaps and the like you will need to experiment with small durations.Try:
1 In order to make the programfool-proof you will need to check to see whether the radius is greater than 87. If so then don't bother to draw the circle.Or you could test for the radiusbeing less than or equal to 87 and if so, draw the circle. Note the meaning of the following relations that are produced by pressing symbol shift and keys on the second row
1 If you know how to read sheet music then try converting printed notes to
1 If you havn't looked at my menu program do so now, please.
1 If you have yet to put a number into a box then your Spectrum doesn't believe that that box exists! Try entering:
1 If you don't know which notes to use then compose by ear (trial and error).
1 How about
1 Furthermore, the Spectrum will not distinguish between capital and lower case letters. It thinks that
1 Experiment with the
1 Experiment with
1 Each note of the tune must have its own
1 E F F# G A
1 Draw your smile out on paper first, then translate it into
1 Don't forget to leave room for
1 Create your own program thatincludes the
1 Coordinates are written in the order: x-coordinate first, comma, then y-coordinate. The Spectrum Manual illustrates the pixel at (191,159) {Dont worry, all will be explained}. Its position is found by looking along the bottom row to find thex-coordinate 191, and marking its position with a finger of your left hand, say. Similarly, point to the y-coordinate with aright hand finger on the right hand side of the diagram. Now move your left finger up and your right finger to the left until both fingers meet. This ispixel 191,159. To make this moreclear run the program found in this Learning Element.
1 Computer people call anything that appears between quotation marks (
1 Colour items can be used in
1 ANameNotUsedYet
1 A menu is a list of optionsone of which the user of the program can select by entering the corresponding number. Your program must, therefore, containan
1 24*32=768 character squaresand 8*8=64 pixels per character square.
1 24 rows, 32 columns.
1 208,3
1 20,20 120
1 127,87;"Circle too big to draw!"
1 127,87,radius:
1 124,84 110
1 120,16
1 100
1 10,10,PI/2 130
1 10,10 110
1 1,16 110
1 0 1 2 3 4 5 6 7 8 9 10 11 Adding or subtracting multiples of 12 to or from
1 .02,33.9 180
1 .02,33.8 170
1 .02,33.5 160
1 .02,32 140
1 .02,30 130
1 .02,27 120
1 .02,23 110
1 (set earlier) and
1 (don't let it see you laughing at it, we all have our faults). This also applies tonames for numeric variables:
1 "yes"="yes"
1 "yes"="no"
1 "What is your name? ":
1 "The square root of ";number;" is ";answer
1 "Hello ";n$
1 "Enter your number";number
1 "Do you want to continue? (y/n) ";a$ 110
1 "Day? ";Day
1 "Continue? ";a$ 110
1 "Bob Dylan"
1 statement has been executed the coordinates that your Spectrum remembers are those last plotted e.g. Spectrum remembers: after
1 means take whatever you find in the box called
1 means is equal to
1 less than or equal to
1 greenhouses and mustard
1 greater than. Modify your program so that it acts in the way we've just described.
1 greater than or equal to
1 goto the selected option
1 etc.although input other than n or yhas a different effect in each case. (Note that
1 draws a semi-cicular curve from 110,20 to 110+20,20+30 (i.e. to 130,50)";
1 do notlie outside the ranges 0-255 and0-175 respectively.
1 but make sure that
1 Write a program that repeatedly asks for a number and then prints a running total and the number of numbers entered so far.
1 These conditions are false:
1 That was a long winded way of drawing; in the next LearningElement you'll see a much easiermethod. Find out how to unplot apixel i.e. change an ink dot to a paper dot. (Hint: try the colour items but not
1 Remember to start variables off with zero before you try to use them! e.g.
1 Remember that you can put a message in your
1 Remember that
1 Notice that the x-coordinates must be whole numbers (integers) and cannot beless than 0 or greater than 255. y-coordinates are integers in the range 0 to 175.
1 tells your Spectrum to jump to line
1 statements.
1 Bdum Bdum!
1 ")?xY1.2;:THEN"
1 statements and one
1 statement.
1 creates a box called
1 Entering
1 then
1 statement.
1 70,61
1 statement, in order to check forthe numbers 1-4. Include some instructions to deal with erroneous input.
1 130,46
1 for the x-axis. Try to place arrow heads on your axes.
1 statement.
1 instructions
1 e.g.
1 0,0 then
1 statement, e.g.
1 120
1 INPUT
1 statements.
1 15
1 80
1 Use a sensible
1 "51+2*6"
1 Dream up a simple program that makes use of the BASIC you've learnt so far.
1 Write a program that gives the number 632.1 to a variable of your choice and then prints thatvariable.
1 I'm desperate for a number!