Exercises

1. Create and execute an anonymous functions (both with standard and short & notation) which calculates square area of:

   • square,
   • rectangle,
   • circle (assume that Pi is 3.14).

2. Rewrite given anonymous functions with & notation:

   • Enum.find([2, 3, 4], fn x -> rem(x, 2) == 1 end)
   • Enum.flat_map_reduce(1..5, 0, fn x, acc -> {[[x]], acc + x} end)

3. Create an anonymous function which meets the criteria:

   • when you pass first_name it will print "Hello User" (where "User" is first_name in this case),
   • when you pass last_name it will print "Hello Example" (where "Example" is last_name in this case),
   • when you pass first_name and last_name it will print "Hello User Example" (where "User" is first_name and "Example" is last_name in this case),
   • when you don't pass any arguments it should print "Who you are?".
   • you should not use any control flow mechanisms,
   • use different function implementations depending on given arguments,
   • use pattern matching to execute proper function implementation based on different arguments.

4. Create an anonymous function which takes two arguments: number and an anonymous function. Your function should execute anonymous function (passed as a second argument) with a number (passed as a first argument). Try it out to perform following operations:

   • multiplying by 10,
   • dividing by 10,
   • add 10 to given number,
   • subtract 10 from given number.

5. Create an anonymous function which takes a number as an argument and returns another function. Execute nested function with another number. Sum of these two numbers should be returned as a result, for example:

     iex> sum.(5).(6)
     11
   

6. Create an anonymous function which performs the division of numbers. Use guard clause not to allow non-numeric arguments and zero as a second argument (in both cases provide feedback as a returned value).