FA-62193 / Currency rounding and FX conversion / Member archive

The disclosed markup is rounded to nearest and can understate · case 03

A markup of 3.504% is disclosed as 3.50%.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

solve(amount, ref_rate, markup_bps, card_exp): amount in merchant currency, ref_rate cardholder units per merchant unit, markup_bps an integer (negative for a promotional discount). The offered rate is ref*(1+bps/10000) rounded half-up to 6 decimals, and the card amount is amount*offered rounded half-up at card_exp. The disclosed markup percentage is (offered/ref - 1)*100 computed from the rounded offered rate and rounded toward positive infinity to 2 decimals so it never understates. Return [offered, card_amount, markup_pct] as strings.

Why this case matters

Currency amounts must be rounded at the right stage and in the right unit, or ledgers, quotes and settlements drift by minor units.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression disclosure-rounding-direction 1	`["31.920634", "5018.562", "1.50"]`	`["31.920634", "5018.562", "1.51"]`	Failed

MEMBER ARCHIVE

The complete case is available to members.

This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

Member access is invitation-based. Sign in with your invited account to inspect the sources.