---
title: "Binary Teacher"
id: 72032
type: "computer_media"
slug: "binary-teacher"
url: "http://localhost/computer_media/binary-teacher/"
markdown_url: "http://localhost/computer_media/binary-teacher.md"
published_at: "2026-10-20T14:07:36+00:00"
modified_at: "2026-10-20T14:20:29+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2026/10/1_BINARY-TEACHER.png"
excerpt: "Converts any number from 0 to 255 into eight binary digits, leaving only the place values that add up to it showing in a row of boxes."
category:
  - name: "Archived Media"
    slug: "archived-media"
    taxonomy: "category"
    url: "http://localhost/category/archived-media/"
post_tag:
  - name: "Downloadable"
    slug: "downloadable"
    taxonomy: "post_tag"
    url: "http://localhost/tag/downloadable/"
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
model:
  - name: "Timex/Sinclair 1000"
    slug: "ts-1000"
    taxonomy: "model"
    url: "http://localhost/model/ts-1000/"
indiv:
  - name: "Gene G. Buza"
    slug: "gene-g-buza"
    taxonomy: "indiv"
    url: "http://localhost/indiv/gene-g-buza/"
genre:
  - name: "Education"
    slug: "education"
    taxonomy: "genre"
    url: "http://localhost/type/education/"
media_contents:
  - id: 72046
    title: "Synchro-Sette May 1984"
    type: "computer_media"
    url: "http://localhost/computer_media/synchro-sette-may-1984/"
media_type: "Program"
programmers:
  - name: "Gene G. Buza"
    slug: "gene-g-buza"
    taxonomy: "indiv"
    url: "http://localhost/indiv/gene-g-buza/"
mediadate: "1984"
images:
  - url: "http://localhost/wp-content/uploads/2026/10/1_BINARY-TEACHER.png"
media_type_tags: "Education"
---

# Binary Teacher

Shows how a decimal number from 0 to 255 is written in binary. The screen has a row of eight boxes, each labelled with its place value from 128 down to 1. When a number is entered, the program fills each box with a 1 or a 0, clears the place values of the 0 bits, and prints the decimal and binary forms with a note that the place values still showing add up to the number. Pressing ENTER starts again.

***

## Program Analysis

### Program Structure

Lines 1000–1190 draw two rows of eight boxes from block-graphic strings, using subroutine 1200 to print each 4-character segment eight times. Lines 1300–1320 print the place values `2**N` under the boxes. The conversion loop (lines 2100–2160) tests `N` against each power of two from 27 down, prints a 1 or 0 in the top row, blanks the place value when the bit is 0, adds the digit to `C$`, and subtracts the place value when the bit is set.

### Notable Techniques

- Clearing the place values of the 0 bits leaves the decomposition on screen, so the user can see which powers of two make up the number.
- Input is taken in `SLOW` mode and the display work is done in `FAST`. Values outside 0–255 are refused and the prompt is repeated.

## Source Code

```
1000 CLS
1010 FAST
1020 PRINT AT 1,7;"█[B][I][N][A][R][Y]█[T][E][A][C][H][E][R]█"
1030 LET A$="▛▀▀▀"
1040 PRINT AT 8,0;
1050 GOSUB 1200
1060 PRINT AT 9,0;
1070 LET A$="▌   "
1080 GOSUB 1200
1090 LET A$="▛▀▀▀"
1100 PRINT AT 10,0;
1110 GOSUB 1200
1120 LET A$="▌   "
1130 PRINT AT 11,0;
1140 GOSUB 1200
1150 LET A$="▀▀▀▀"
1160 PRINT AT 12,0;
1170 GOSUB 1200
1180 PRINT AT 12,0;AT 8,31;"▜";AT 9,31;"▐";AT 10,31;"▜";AT 11,31;"▐";
1190 GOTO 1300
1200 FOR N=1 TO 8
1210 PRINT A$;
1220 NEXT N
1230 RETURN
1300 FOR N=7 TO 0 STEP -1
1310 PRINT AT 11,29-(N*4);2**N
1320 NEXT N
1330 LET C$=""
2000 PRINT AT 21,0;"INPUT A NUMBER BETWEEN 0 AND 255";
2010 SLOW
2020 INPUT N
2025 FAST
2030 IF N<0 OR N>255 THEN GOTO 2020
2040 LET NN=N
2100 FOR I=1 TO 8
2110 IF N>=2**(8-I) THEN LET B$="1"
2120 IF N<2**(8-I) THEN LET B$="0"
2130 PRINT AT 9,I*4-3;B$
2140 IF B$="0" THEN PRINT AT 11,I*4-3;"   ";
2145 LET C$=C$+B$
2150 IF N>=2**(8-I) THEN LET N=N-2**(8-I)
2160 NEXT I
2170 PRINT AT 4,0;NN;" DECIMAL = ";C$;" BINARY"
2180 PRINT AT 16,0;"THESE NUMBERS ADDED TOGETHER    EQUAL ";NN
2190 PRINT AT 11,31;"▐";AT 21,0;"PRESS ENTER TO RECYCLE :::      ";
2200 PAUSE 40000
2210 CLS
2220 RUN 
9998 SAVE "BINARY TEACHE[R]"
9999 RUN
```