interfaces_code_snippet_23.go

type calculator interface {
	add(a, b int) int
	sub(a, b int) int
	div(a, b int) int
	mul(a, b int) int
}

type mockCalculator struct {
	calculator // Embeds the calculator interface
}

func (m *mockCalculator) add(a, b int) int { return a + b }

func summarize(calc calculator, values ...int) int {
	var result int
	
	for _, val := range values {
		result = calc.add(result, val)
	}
	
	return result
}

func main() {
	mock := new(mockCalculator)
	result := summarize(mock, 10, 12, 9, 11)
	fmt.Println(result) // Prints 42
}