The use of the variable name is optional, but if you are using many loops in a
program, including the name makes the program easier to follow.
You can change the step size so that count does not increase by 1:
20 FOR count=7 TO 50 STEP 2
The step size can be decimal:
20 FOR count=3 TO 10 STEP 1.6
It can even be negative, although the start and end values for the loop must
also be adjusted so that the loop starts with the highest value:
20 FOR count=20 TO 1 STEP -1
Of course, the loop values can also be variables. You can experiment with loops
by adding these lines and running the program a few times:
15 INPUT "What is the start, end and step size ",start,end,step
20 FOR count=start TO end STEP step
Here is a brief program which shows the power of the loop:
10 MODE 2
20 PR0Cmodern_art
30 END
40 DEFPR0Cmodern_art
50 FOR count=l TO 50
60 PR0Ccircle(RND(1279) ,RND(1023) ,RND(200),RND(7))
70 NEXT count
80 ENDPROC
90 DEFPR0Ccircle(xcentre%,ycentre%,radius%,colour%)
100 GCOL 0,colour%
110 MOVE xcentre%,ycentre%
120 PLOT 157,xcentre%+radius%,ycentre%
130 ENDPROC
RND produces a random whole number between 1 and the bracketed value.
Line 60 draws a random-sized circle in a random position and random colour by
calling PROCcircle with random parameters.
You may get an idea how some of the Welcome software works by running the
program again using these lines:
50 FOR count=7 TO 1 STEP -1
60 PR0Ccircle(640,512,count*50,count)
C 38