add: an exercise to error handling

This commit is contained in:
Inanc Gumus
2019-05-17 11:14:54 +03:00
parent 99860abef8
commit 5c1364e181
4 changed files with 74 additions and 1 deletions

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@@ -0,0 +1,33 @@
package main
import "fmt"
// ---------------------------------------------------------
// EXERCISE: Refactor
//
// In the headerOf function, instead of using a switch,
// use a map. Declare it at the package-level.
//
// RESTRICTION
//
// For panicking, use a deferred function and a named param.
//
// EXPECTED OUTPUT
//
// Please run the solution.
//
// ---------------------------------------------------------
func main() {
fmt.Println(headerOf("gif"))
}
func headerOf(format string) string {
switch format {
case "png":
return "\x89PNG\r\n\x1a\n"
case "jpg":
return "\xff\xd8\xff"
}
panic("unknown format: " + format)
}

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@@ -0,0 +1,28 @@
// For more tutorials: https://blog.learngoprogramming.com
//
// Copyright © 2018 Inanc Gumus
// Learn Go Programming Course
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
//
package main
import "fmt"
func main() {
fmt.Println(headerOf("gif"))
}
var headers = map[string]string{
"png": "\x89PNG\r\n\x1a\n",
"jpg": "\xff\xd8\xff",
}
func headerOf(format string) (header string) {
defer func() {
if header == "" {
panic("unknown format: " + format)
}
}()
return headers[format]
}

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@@ -0,0 +1,11 @@
# Header
What you will learn?
1. **[Refactor](https://github.com/inancgumus/learngo/tree/master/28-error-handling/exercises/01-refactor)**
Refactor the headerOf function with a map + defer + and a named param.
2. **[text](https://github.com/inancgumus/learngo/tree/master/)**
text

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@@ -14,7 +14,8 @@ import (
"os"
)
// Detect returns only the valid filenames that match to a header of the given format.
// Detect returns the files that have a valid header (file signature).
// A valid header is determined by the format.
func Detect(format string, filenames []string) (valids []string, err error) {
defer func() {
if rerr := recover(); rerr != nil {