Capstone Brief: Requirements

The product

A Personal Finance Manager — record transactions, categorize them, and answer real questions: what did I spend, on what, and what remains?

Features (graded subset marked ★)

1. ★ Record a transaction: name, category, amount (positive = income, negative = expense).
2. ★ Validate at the boundary: empty name rejected, zero amount rejected.
3. ★ Balance: sum of all amounts.
4. ★ By category: per-category totals (map<string,double>).
5. Filter: transactions above/below a threshold.
6. Persistence: save/load CSV lines (name,category,amount) — module 6's parser in production.
7. Report: sorted summary printed via void program().

Architecture constraints

• A Transaction struct; an enum class Kind { Income, Expense } derived from the sign.
• A class Ledger owning a std::vector<Transaction> — its methods enforce validation (module 10's invariant discipline).
• Parsing/formatting as free functions (module 16's pipeline), not glued into Ledger.
• No new/delete anywhere (module 12), no C-strings, no using namespace std; in headers.

Milestones

M1: struct + Ledger with record/balance. M2: category totals + filter. M3: CSV save/load round-trip. M4: report via program(). Ship each milestone working — the graded checks map to M1–M3 exactly.

Acceptance (the tests' point of view)

The graded challenges call your names directly: add_record, balance, category_totals, plus a program() report check. Edge cases are graded: the empty ledger, the rejected record, the single-category month. Design for them from line one.