Introduction
Numbers in Clojure include:
- Integers: numbers with no digits behind the decimal separator (whole numbers). Examples are
-6, 0, 1, 25, 976 and 500000.
- Floating-point numbers: numbers with zero or more digits behind the decimal separator. Examples are
-2.4, 0.1, 3.14, 16.984025 and 1024.0.
Two common numeric types are int and float. An int is a 32-bit integer and a float is a 64-bit floating-point number.
Arithmetic is done using the standard arithmetic operators. Numbers can be compared using the standard numeric comparison operators (>, <, <=, >=), the equality operator (=) and the non-equality operator (not=).
In this exercise you must conditionally execute logic. A common way to do this in Clojure is by using cond:
(cond (= x 5) "Expression to evaluate when x equals 5"
(> x 7) "Expression to evaluate when x is greater than 7"
:else "Expression to evaluate in all other cases")
Note
The == operator might be preferable to = in some cases where numbers need to be compared irrespective of the exact type. For instance,
(== 5.0 5) ;; true as both numbers are equal when type is ignored
(= 5.0 5) ;; false as the types of numbers are also taken into account here i.e. float is different from int
The Clojure guide on Equality, specifically the section on Numbers goes into more details.
Instructions
In this exercise you'll be writing code to analyze the production of an assembly line in a car factory. The assembly line's speed can range from 0 (off) to 10 (maximum).
At its lowest speed (1), 221 cars are produced each hour. The production increases linearly with the speed. So with the speed set to 4, it should produce 4 * 221 = 884 cars per hour. However, higher speeds increase the likelihood that faulty cars are produced, which then have to be discarded. The following table shows how speed influences the success rate:
-
0: 0% success rate.
-
1 to 4: 100% success rate.
-
5 to 8: 90% success rate.
-
9: 80% success rate.
-
10: 77% success rate.
You have two tasks.
1. Calculate the production rate per hour
Implement the production-rate function to calculate the assembly line's production rate per hour, taking into account its success rate:
(production-rate 6)
;;=> 1193.4
Note that the value returned is a double.
2. Calculate the number of working items produced per minute
Implement the working-items function to calculate how many working cars are produced per minute:
(working-items 6)
;;=> 19
Note that the value returned is an int.
Learning Exercise
