Some solutions for the julia path

julia/currency-exchange/HINTS.md

@@ -0,0 +1,41 @@
+# Hints
+
+## General
+
+## 1. Estimate value after exchange
+
+- You can use the [division operator][division-operator] to get the value of exchanged currency.
+
+## 2. Calculate currency left after an exchange
+
+- You can use the [subtraction operator][subtraction-operator] to get the amount of change.
+
+## 3. Calculate value of bills
+
+- You can use the [multiplication operator][multiplication-operator] to get the value of bills.
+
+## 4. Calculate number of bills
+
+- You need to divide `amount` into `denomination`.
+- To remove decimal places from a floating point value, you can use the [`floor()`][floor] function.
+- You need an integer to get the exact number of bills.
+ The `floor` function can take the desired output type as a parameter.
+
+  **Note:** The [`÷` operator][div], or `div()` function, also does floor division. However, if an operand is floating point the result is still floating point.
+
+## 5. Calculate leftover after exchanging into bills
+
+- You need to find the remainder of `amount` that does not equal a whole `denomination`.
+- The [Modulo operator][div] `%` can help find the remainder.
+
+## 6. Calculate value after exchange
+
+- You need to calculate `spread` percent of `exchange_rate` using multiplication operator and add it to `exchange_rate` to get the exchanged currency.
+- The actual rate needs to be computed. Remember to add exchange _rate_ and exchange _fee_.
+- You can get exchanged money affected by commission by using a divide operation, plus type casting to integer if necessary.
+
+[division-operator]: https://docs.julialang.org/en/v1/manual/mathematical-operations/#Arithmetic-Operators
+[multiplication-operator]: https://docs.julialang.org/en/v1/manual/mathematical-operations/#Arithmetic-Operators#Arithmetic-Operators
+[subtraction-operator]: https://docs.julialang.org/en/v1/manual/mathematical-operations/#Arithmetic-Operators
+[floor]: https://docs.julialang.org/en/v1/base/math/#Base.floor
+[div]: https://benlauwens.github.io/ThinkJulia.jl/latest/book.html#_floor_division_and_modulus