In this episode I’m demonstrating how to print numbers in evenly spaced columns in Commodore BASIC.
On the C128 and the Plus/4 we can use a nifty little function called PRINT USING for this, with which we can format the output of any printed text or variable.
On the C64 and VIC-20 that function doesn’t exist, so we’ll have to convert a numeric value into a string (using the STR$ function), and then determine how long our string is. Following that we’ll have to manually pad our string value with as many spaces as are required.
BASIC 3.5 / BASIC 7
Here’s the full code for the C128 and Plus/4, which is based on my earlier Lottery Number generator listing. PRINT USING appears in line 120:
10 x=rnd(-ti)
20 for i=1 to 6
30 rn=int(rnd(1)*49)+1
40 for j=1 to i
50 if n(j)=rn then 30
60 next j
70 n(i)=rn
80 next i
100 print:gosub 200
110 for i=1 to 6
120 print using "#####";n(i);
130 next
140 print
199 goto 20
200 rem bubble sort
210 for i=5 to 1 step -1
220 for j=1 to i
230 x=n(j):y=n(j+1)
240 if x>y then n(j)=y:n(j+1)=x
250 next:next
299 return
BASIC 2.0
And here’s the same listing without PRINT USING for the C64 and VIC-20. The string formatting happens in the subroutine in line 300:
10 x=rnd(-ti)
20 for i=1 to 6
30 rn=int(rnd(1)*49)+1
40 for j=1 to i
50 if n(j)=rn then 30
60 next j
70 n(i)=rn
80 next i
100 print:gosub 200
110 for i=1 to 6
120 gosub 300:print a$;
130 next
140 print
199 goto 20
200 rem bubble sort
210 for i=5 to 1 step -1
220 for j=1 to i
230 x=n(j):y=n(j+1)
240 if x>y then n(j)=y:n(j+1)=x
250 next:next
299 return
300 rem space the numbers
310 a$=str$(n(i))
320 if len(a$)=2 then a$=" "+str$(n(i))
399 return
Any questions, please let me know. Happy retro hacking!
PS: It got a bit dark there at the end on my webcam. Help me get some lights by supporting me on Patreon 😉