Chapter 5. Conditionals and Recursion
The main topic of this chapter is the if statement, which executes different code depending on the state of the program. But first I want to introduce two new operators: floor division and modulus.
Floor Division and Modulus
The floor division operator, ÷ (\div TAB), divides two numbers and rounds down to an integer. For example, suppose the running time of a movie is 105 minutes. You might want to know how long that is in hours. Conventional division returns a floating-point number:
julia>minutes=105105julia>minutes/601.75
But we don’t normally write hours with decimal points. Floor division returns the integer number of hours, rounding down:
julia>hours=minutes÷601
To get the remainder, you could subtract one hour in minutes:
julia>remainder=minutes-hours*6045
An alternative is to use the modulus operator, %, which divides two numbers and returns the remainder:
julia>remainder=minutes%6045
The modulus operator is more useful than it seems. For example, you can check whether one number is divisible by another—if x % y is 0, then x is divisible by y.
Also, you can extract the rightmost digit or digits from a number. For example, x % 10 yields the rightmost digit of an integer x (in base 10). Similarly, x % 100 yields the last two digits.
Boolean Expressions
A Boolean expression is an expression that is either true or false. The following examples use the operator ==, which compares two operands and produces ...