Quote

This program is a job cost estimator that calculates and prints a formatted quote for installation work, covering materials, shop labour, on-site labour, overhead, and profit. The user can choose to enter costs either as a single total or itemised line by line, with the itemisation routine (subroutine at line 1200) reused for materials, shop labour, and on-site labour. All monetary values are rounded to two decimal places using the classic INT(100*X+.05)/100 idiom before display. The quote summary is printed via a dedicated subroutine at line 3000, showing both per-unit and extended (total) figures in a tabulated layout using TAB stops.

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Program Analysis

Program Structure

The program is organised into a main routine and three subroutines, with the main flow running from lines 10–690 and looping back to line 100 for repeated estimates. The global counter D (initialised at line 20, incremented at line 205) tracks the estimate number across sessions.

Line Range	Purpose
10–20	Initialisation: CLS, set estimate counter D=0
100–690	Main loop: title display, user prompts, cost collection, quote display, loop back
1000–1190	Subroutine: material cost entry (itemised or lump sum)
1200–1670	Subroutine: generic itemised cost entry, accumulating into C
2000–2550	Subroutine: shop and on-site labour entry (itemised or lump sum)
3000–3270	Subroutine: formatted quote printout
9998–9999	SAVE with auto-run flag, then RUN

Itemised Entry Subroutine (Lines 1200–1670)

The subroutine at line 1200 is a reusable itemised cost collector. It loops, prompting for item name, unit cost, and quantity, computing the extended cost (E = A * G), and accumulating the running total in C. Entry of a blank item name (B$="" at line 1255) terminates the loop. The result is returned in C, which the calling code then assigns to the appropriate variable (M, L, or H). This reuse of a single subroutine for three different cost categories is the most structurally notable aspect of the program.

There is a variable name collision hazard: C is used both as the overhead percentage (entered at line 410 and used in the formula at line 430) and as the accumulator inside the itemised entry subroutine (line 1200). After an itemised entry call, C is immediately copied to the target variable (lines 1155, 2120), but the overhead percentage previously stored in C is overwritten if itemisation is called after line 410 — however, in the actual execution order, overhead is collected after all labour and material subroutines have returned, so in practice this does not corrupt the overhead value during normal flow. The overhead percentage value in C is still correctly used at line 3200 for display.

Cost Calculation (Lines 550–640)

The quote calculations at lines 550–640 derive all figures from the per-unit costs and the installation count Q:

• B = Q * M — total materials
• K = Q * L — total shop labour
• J = H * Q — total on-site labour
• V = O * (L + H) — overhead per unit (percentage of direct labour)
• W = V * Q — total overhead
• R = P * (B + K + J + W) — total profit
• X = R / Q — profit per unit
• S = B + K + J + R + W — total job quote
• T = S / Q — quote per unit

Rounding Technique

Monetary values are rounded to two decimal places just before display using the standard fixed-point idiom INT(100*X+.05)/100. This appears both in the itemised entry loop (line 1455) and throughout the summary subroutine (lines 3102–3256). The +.05 bias provides conventional rounding (round half up) rather than truncation.

SCROLL-Based Display

The program uses SCROLL extensively to control screen layout rather than CLS, producing a continuous paper-tape style output. Multiple consecutive SCROLL calls are used to create blank-line spacing between sections. CLS is reserved for major section transitions (title screen, start of quote entry, itemised cost screens).

Input Validation

Yes/No prompts are validated by checking the first character of the input string (e.g. B$(1)="Y"). If neither “Y” nor “N” is matched, execution falls through to a GOTO back to the INPUT line, forming a simple validation loop. This pattern appears at lines 1050–1070, 2040–2060, 2290–2310.

Notable Anomalies

• Line 1155 assigns M=C after the itemised material subroutine, but note that the subroutine itself uses C as its accumulator, overwriting the overhead percentage if overhead were collected before this point. In the actual execution order this is safe, but the reuse of C for two distinct purposes is fragile.
• The spelling “INSTALATIONS” (one ‘l’) at line 3080 is a typo in the output text.
• Line 2130 uses GOTO 2240 to skip the lump-sum shop labour input block, jumping directly to the on-site labour section — a straightforward forward jump with no structural issue.
• The INPUT Y$ at line 220 and line 530 simply waits for Enter; the content of Y$ is discarded, making these effectively “press Enter to continue” pauses.