Explore fun brain teasers to hone your logic, critical thinking, and problem-solving skills. Gain insights into Go and practice to avoid future mistakes.

go.tar.gz

Go lang

Who knew puzzles could be fun? Puzzles and brain teasers are a great way to practice your critical thinking and improve your logic and problem-solving skills. This course provides a basic understanding of Go. The teasers in this course will help you practice what you already know and help avoid future mistakes.

Go Brain Teasers

# Try it yourself ##
Try executing the code below to see the result for yourself.

package main

import (
	"fmt"
)

func main() {
	n := 1.1
	fmt.Println(n * n)
}



# Explanation ##
You might have expected **`1.21`**, which is the right mathematical answer.

When seeing this or similar output, some new developers come to the message boards and say, “We found a bug in Go!” The usual answer is, “Read the manual” (RTM).

> According to Grant Edwards, *“Floating point is sort of like quantum physics: the closer you look, the messier it gets.”*


The basic idea behind this issue is that in floating points, we sacrifice accuracy for speed. Don’t be shocked; it’s a trade-off we often do in computer science.

The result we see conforms with the floating-point specification. If we run the same code in Python, Java, C … you will see the same output.

Remember that floating-point numbers are not accurate, and accuracy worsens as the number gets bigger. One implication is that, when testing with floating points, we need to check for “roughly equal” and decide on an acceptable threshold. Testing libraries such as `stretchr/testify` have ready-made functions (such as `InDelta`) to check if two floating numbers are approximately equal.

Floating points have several other oddities. For example, there’s a particular `NaN` value (short for “not a number”). The `NaN` value does not equal any number, including itself. The following code prints `false`:

```
fmt.Println(math.NaN() == math.NaN())
```

> **Note**: To verify if you get `NaN`, you need to use a special function such as `math.IsNaN`. If you need better accuracy, look into `math/big` or external packages such as `shopspring/decimal`.

Understand how float numbers can be different from calculated numbers. 

Puzzle 7 Explanation: NaN

Understand how float numbers can be different from calculated numbers.

Before We Begin

Puzzles

Wrapping Up

Puzzle 7 Explanation: NaN

Try it yourself