72 lines
1.9 KiB
Markdown
72 lines
1.9 KiB
Markdown
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## How to fix this program?
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```go
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package main
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import (
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"fmt"
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"time"
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)
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func main() {
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if err != nil; d, err := time.ParseDuration("1h10s") {
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fmt.Println(d)
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}
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}
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```
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1. Swap the simple statement with the `err != nil` check. *CORRECT*
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2. Remove the error handling.
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3. Remove the semicolon.
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4. Change the short declaration to an assignment.
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> **1:** Yes. In a short if statement, the simple statement (the short declaration there) should be the first part of it. Then, after the semicolon separator, there should be a condition expression.
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>
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> **2:** You don't want that. That's not the issue here.
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## What does this program print?
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```go
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package main
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import "fmt"
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func main() {
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done := false
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if done := true; done {
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fmt.Println(done)
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}
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fmt.Println(done)
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}
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```
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1. true and true
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2. false and false
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3. true and false *CORRECT*
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4. false and true
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> **3:** Yes. It shadows the main()'s done variable, and inside the if statement, it prints "true". Then, after the if statement ends, it prints the main()'s done variable which is "false".
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## How can you fix this code?
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```go
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package main
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import "fmt"
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func main() {
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done := false
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if done := true; done {
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fmt.Println(done)
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}
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fmt.Println(done)
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}
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```
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1. Remove the first declaration (main()'s done)
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2. Remove the declaration in the short-if (if's done)
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3. Change the done declaration of the main() to an assignment
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4. Change the done declaration of the short-if to an assignment. And, after the if statement, assign false back to the done variable. *CORRECT*
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> **1:** That will break the program. The last line tries to print it.
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>
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> **2:** The program wants to use it to print true.
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>
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> **3:** There will be "undefined variable" error.
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> **4:** Yes, that will solve the shadowing issue. Short-if will reuse the same done variable of the main(). And, after the short-if, done will be false because of the assignment, and it will print false.
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