---
title: "Identify Above Average Sale"
id: 57233
type: "computer_media"
slug: "identify-above-average-sale"
url: "http://localhost/computer_media/identify-above-average-sale/"
markdown_url: "http://localhost/computer_media/identify-above-average-sale.md"
published_at: "2024-10-04T06:56:38+00:00"
modified_at: "2026-03-30T21:19:11+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2024/10/123_Sale.png"
excerpt: "Enter ten sales figures and this BASIC program instantly flags which ones beat the average — a neat two-pass array technique worth studying."
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/"
genre:
  - name: "Business"
    slug: "business"
    taxonomy: "genre"
    url: "http://localhost/type/business/"
media_contents:
  - id: 56734
    title: "Timex Sinclair Public Domain Library Tape 1003"
    type: "computer_media"
    url: "http://localhost/computer_media/timex-sinclair-public-domain-library-tape-1003/"
media_type: "Program"
mediadate: "198x"
images:
  - url: "http://localhost/wp-content/uploads/2024/10/123_Sale.png"
media_type_tags: "Business"
---

# Identify Above Average Sale

This program collects ten sales figures from the user, computes their arithmetic mean, then prints each figure — flagging those that exceed the average with the message “IS AN ABOVE AVERAGE SALE”. It uses a single-dimensional array S(10) to store all values before the comparison pass, requiring two separate loops: one for input and one for output. The conditional branch at line 120 uses a GOTO to skip the plain PRINT and reach the annotated PRINT at line 150, a common two-path idiom in early BASIC. All ten values are always printed, whether above average or not.

***

## Program Analysis

### Program Structure

The program divides cleanly into three phases: initialisation, input collection, and results display.

1. **Initialisation (lines 20–30):** Declares the array `S(10)` and zeroes the accumulator `T`.
2. **Input loop (lines 40–80):** Iterates `I` from 1 to 10, prompting for and storing each sale value, accumulating the total in `T`.
3. **Reporting loop (lines 90–160):** Computes the average `AVG=T/10`, then iterates over the array, printing each value with or without an annotation.

### Key BASIC Idioms

The conditional display at lines 120–160 is a classic two-branch GOTO pattern. If `S(I)>AVG`, execution jumps to line 150 (annotated print); otherwise it falls through to line 130 (plain print) and then jumps over line 150 via line 140. This avoids an `IF…ELSE` construct, which standard BASIC does not provide.

### Variable Summary

| Variable | Purpose |
| --- | --- |
| `S(10)` | Array holding the ten sales figures |
| `T` | Running total of all sales |
| `I` | Loop counter for both FOR loops |
| `AVG` | Computed arithmetic mean (`T/10`) |

### Notable Techniques

- Storing all values in an array before comparison requires keeping all ten figures in memory simultaneously; a streaming approach could compute the average and re-prompt, but two-pass array storage is more straightforward here.
- The divisor in `AVG=T/10` is hard-coded to match the array size and loop bound — changing any one of the three would require updating all three manually.
- The blank `PRINT` at line 100 inserts a visual separator between the input phase and the output phase.

### Bugs and Anomalies

- Lines 180 and 190 (`SAVE` and `RUN`) appear after `STOP` at line 170 and are unreachable during normal execution; they serve as a save-and-restart mechanism invoked only if the user manually executes those lines or the program is re-entered.
- The program prints *all* values regardless of whether they are above average or not; items at or below the average are printed without annotation, which may not match the intention implied by the title “IDENTIFY ABOVE AVERAGE SALE” — one might expect below-average sales to be suppressed entirely.
- There is no input validation; entering a non-numeric value will cause an error.

## Source Code

```
   5 REM IDENTIFY ABOVE AVERAGE SALE
  20 DIM S(10)
  30 LET T=0
  40 FOR I=1 TO 10
  50 PRINT "ENTER SALE"
  60 INPUT S(I)
  70 LET T=T+S(I)
  80 NEXT I
  90 LET AVG=T/10
 100 PRINT 
 110 FOR I=1 TO 10
 120 IF S(I)>AVG THEN GOTO 150
 130 PRINT S(I)
 140 GOTO 160
 150 PRINT S(I);" IS AN ABOVE AVERAGE SALE"
 160 NEXT I
 170 STOP 
 180 SAVE "1012%3"
 190 RUN
```