Values, types, and functions

The idea

Julia values have types, and functions can often work with several compatible types without annotating every argument. A variable name refers to a value; an annotation should express a useful constraint rather than merely repeat something obvious. Define a short function with an assignment form or use a function block for several steps. The last evaluated expression supplies the result unless an explicit return exits earlier.

The / operator performs division, while ÷ requests integer division when its arguments are integers. Choose the operation that matches the problem before deciding how to display the answer. Parentheses make evaluation order clear. A function that returns its result is easier to reuse than one that only prints, so keep calculation and presentation as separate responsibilities in a small program.

pages_per_day(pages, days) = pages / days
function remaining_pages(total, completed)
    total - completed
end
println(pages_per_day(9, 2))
println(9 ÷ 2)
println(remaining_pages(12, 5))

4.5
4
7

The first calculation retains a fractional quotient. Integer division returns the whole quotient, and the block function returns its final subtraction expression.