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.

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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.