What if the calculation of the commission results in 15 decimal places?

If the calculation of the commission results in 15 decimal places, it is usually too high precision for financial operations and can lead to rounding errors and display inconveniences.

In such cases, rounding to a fixed number of decimal places, such as 2 or 4, depending on business requirements and currency, is applied. This can be done using:

• Mathematical functions (e.g., math.Round in Go).
• Specialized libraries for handling monetary values that store amounts in integer form (e.g., cents) or use decimal types.

Example in Go with rounding to 2 decimal places:

import (
    "fmt"
    "math"
)

func roundToTwoDecimals(val float64) float64 {
    return math.Round(val*100) / 100
}

func main() {
    commission := 0.123456789012345
    rounded := roundToTwoDecimals(commission)
    fmt.Printf("Commission: %.2f\n", rounded) // Commission: 0.12
}

Thus, it is important to define business rules for precision and strictly follow them to avoid issues with financial calculations.