Go

If you are a Gopher, you probably heard some advice that goes like this: when you edit a value then use a pointer receiver, when you read use a value receiver. That’s not always correct and you should be careful when using them. Issue Today I encountered an issue which can be simplified by the bellow code snippet: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 package main import ( "fmt" "time" ) type Counter struct { Count int } // Method with pointer receiver func (c *Counter) Increment() { go func() { for i := 0; i < 10; i++ { c.Count++ time.Sleep(1 * time.Second) } }() } // Method with value receiver func (c Counter) Display() { go func() { for i := 0; i < 10; i++ { fmt.Println("counter value: ", c.Count) time.Sleep(1 * time.Second) } }() } func main() { c := Counter{Count: 0} c.Display() c.Increment() time.Sleep(15 * time.Second) fmt.Println("counter final value: ", c.Count) } I have a struct with two methods, Increment uses the pointer receiver to change the property of the struct, and Display uses the value receiver to read the value from the struct. Here is the result: ...

You may have heard about 0.1 + 0.2 != 0.3 already, it’s a common issue in most programming languages. The reason behind that is the floating point (IEEE 754) as the computer can’t represent exactly a decimal in binary. By utilizing the floating point, the computer can hold a very large decimal, but the trade-off is it now can only represent the approximate of the true value. However, in this post, I will not explain how floating point works but something else – constant. ...