# 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, `//`, divides two numbers and rounds down to an integer. For example, suppose the run 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:

```>>> minutes = 105
>>> minutes / 60
1.75```

But we don’t normally write hours with decimal points. Floor division returns the integer number of hours, rounding down:

```>>> minutes = 105
>>> hours = minutes // 60
>>> hours
1```

To get the remainder, you could subtract off one hour in minutes:

```>>> remainder = minutes - hours * 60
>>> remainder
45```

An alternative is to use the modulus operator, `%`, which divides two numbers and returns the remainder:

```>>> remainder = minutes % 60
>>> remainder
45```

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 zero, then `x` is divisible by `y`.

Also, you can extract the right-most digit or digits from a number. For example, `x % 10` yields the right-most digit of `x` (in base 10). Similarly `x % 100` yields the last two digits.

If you are using Python 2, division works differently. The division operator, `/`, performs floor division if both operands are integers, and floating-point division ...

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