Add errors

errors/errors.go

@@ -0,0 +1,60 @@
+package errors
+
+import (
+	"errors"
+	"fmt"
+)
+
+var ErrDivisionByZero = errors.New("cannot divide by zero")
+
+func divide(a, b float64) (float64, error) {
+	if b == 0 {
+		return -1, ErrDivisionByZero
+	}
+
+	return a / b, nil
+}
+
+func isMultipleOf(a, b float64) (bool, error) {
+	for {
+		if a == 1 {
+			return true, nil
+		}
+
+		if a < 1 {
+			return false, nil
+		}
+
+		if val, err := divide(a, b); err != nil {
+			return false, fmt.Errorf("error during divide() op: %w", err)
+		} else {
+			a = val
+		}
+	}
+
+	return false, nil
+}
+
+func Errors() {
+	if val, err := divide(1, 0); err != nil {
+		fmt.Printf("Got error: %v\n", err)
+	} else {
+		fmt.Printf("1 / 0 = %f\n", val)
+	}
+
+	if _, err := isMultipleOf(6, 2); err != nil {
+		fmt.Printf("Got error: %v\n", err)
+	} else {
+		fmt.Printf("6 is a multiple of 2\n")
+	}
+
+	if _, err := isMultipleOf(6, 0); err != nil {
+		fmt.Printf("Got error: %v\n", err)
+
+		if errors.Is(err, ErrDivisionByZero) {
+			fmt.Printf("We encountered a division by zero error!\n")
+		}
+	} else {
+		fmt.Printf("6 is a multiple of 0\n")
+	}
+}