karanpratapsingh/learn-go

Master the fundamentals and advanced features of the Go programming language

learn-go's Issues

String Formatting example on percentages has error

Problem

In the String Formatting section, the example on percentages is wrong.
It says

...
percent := (3/5) * 100
fmt.Printf("%f", percent)
...

and outputs the result as

$ go run main.go
58.181818

This is wrong for 2 reasons.

1. 3/5 returns an integer 0 and go would complain about the type and formatting discrepancy (%!f(int=0)).
2. Even if it were to be written as 3.0/5 (to have the value of percent be a float), that value would be 60.000000, not 58.181818
   See playground here

Suggested solution

For clarity, I suggest we use another example to illustrate this. See below

...
percent := (7.0 / 9) * 100
fmt.Printf("%f", percent)
...

$ go run main.go
77.777778 

and subsequently...

...
percent := (7.0 / 9) * 100
fmt.Printf("%.2f %%", percent)
...

$ go run main.go
77.78 %

See playground here

Links:

• https://www.karanpratapsingh.com/courses/go/string-formatting

License ?

Could you put a license on your great work ?

Slice part has a error

There is an error in this append function, s1 s2 a1 and a2, written error.

Small typo in slices chapter

Hi there,

thanks for this guide.
I found a small mistake which could be misleading as it shows wrong usage of the slice. You are showing this code snippet

func main() {
	a := [5]int{20, 15, 5, 30, 25}

	s := a[1:4]

	// Output: Array: [20 15 5 30 25], Length: 5, Capacity: 5
	fmt.Printf("Array: %v, Length: %d, Capacity: %d\n", a, len(a), cap(a))

	// Output: Slice [15 5], Length: 3, Capacity: 4
	fmt.Printf("Slice: %v, Length: %d, Capacity: %d", s, len(s), cap(s))
}

But the actual output of the slice is

// Output: Slice [15 5 30], Length: 3, Capacity: 4
                       ^^

Missing pprof and debug lesson