Add solution for Challenge 2 by nasseredine #761
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WalkthroughIntroduces a new Go solution file for Challenge 2 in a user submission directory that reads a line from standard input, reverses it using an external utility function, and prints the result. Changes
Estimated code review effort🎯 1 (Trivial) | ⏱️ ~3 minutes Possibly related PRs
Pre-merge checks❌ Failed checks (1 warning)
✅ Passed checks (2 passed)
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| "fmt" | ||
| "os" | ||
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| "golang.org/x/example/hello/reverse" |
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🧩 Analysis chain
Avoid using example repositories as production dependencies.
The golang.org/x/example/hello/reverse package is from an example/tutorial repository, not intended for production use. Example code may change without notice and lacks API stability guarantees.
Consider implementing the string reversal directly or using a well-established utility library. For a simple reversal, a local implementation would be more appropriate:
- "golang.org/x/example/hello/reverse"Then update the ReverseString function with a proper implementation (see separate comment).
First, verify the package availability and check its documentation:
🌐 Web query:
golang.org/x/example/hello/reverse package documentation and intended use
💡 Result:
Summary — what it is and how to use it
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The package golang.org/x/example/hello/reverse is a tiny example library whose purpose is to reverse values (primarily strings) rune-wise. It exposes a single exported function: String(s string) string, which returns the input string reversed (by runes). [1]
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Intended use: it’s part of the golang.org/x/example collection and exists as a teaching/example package (used by the hello example program and tutorials) to demonstrate how to write a simple library, how to convert between string and []rune, and how to write examples/tests. You can import it in your code (import "golang.org/x/example/hello/reverse") and call reverse.String("hello") to get "olleh". [2][3]
References
- Package documentation (pkg.go.dev): golang.org/x/example/hello/reverse — docs and the String function. [1]
- hello command and usage (shows -r reverse option and links to reverse package). [2]
- golang.org/x/example README (explains purpose of hello and reverse as examples). [3]
Remove the example package dependency and implement string reversal locally.
The golang.org/x/example/hello/reverse package is part of the golang.org/x/example collection and exists as a teaching/example package, not intended for production use. Using educational example code as a production dependency introduces maintenance risks and violates best practices.
Remove the import:
- "golang.org/x/example/hello/reverse"Implement ReverseString locally using a simple rune-based reversal instead of relying on the example package.
Committable suggestion skipped: line range outside the PR's diff.
🤖 Prompt for AI Agents
In challenge-2/submissions/nasseredine/solution-template.go around line 8,
remove the import of "golang.org/x/example/hello/reverse" and replace usage with
a local ReverseString implementation: add a function that converts the input to
[]rune, reverses the rune slice in-place, and returns string(runes); then update
call sites to use the local ReverseString and remove the now-unused import.
| func main() { | ||
| // Read input from standard input | ||
| scanner := bufio.NewScanner(os.Stdin) | ||
| if scanner.Scan() { | ||
| input := scanner.Text() | ||
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| // Call the ReverseString function | ||
| output := ReverseString(input) | ||
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| // Print the result | ||
| fmt.Println(output) | ||
| } | ||
| } |
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Add error handling for scanner failures.
The code doesn't check for scanner errors after Scan() returns false. This means actual read errors are silently ignored, making debugging difficult.
Apply this diff to add proper error handling:
func main() {
// Read input from standard input
scanner := bufio.NewScanner(os.Stdin)
if scanner.Scan() {
input := scanner.Text()
// Call the ReverseString function
output := ReverseString(input)
// Print the result
fmt.Println(output)
}
+ // Check for scanner errors
+ if err := scanner.Err(); err != nil {
+ fmt.Fprintf(os.Stderr, "Error reading input: %v\n", err)
+ os.Exit(1)
+ }
}📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| func main() { | |
| // Read input from standard input | |
| scanner := bufio.NewScanner(os.Stdin) | |
| if scanner.Scan() { | |
| input := scanner.Text() | |
| // Call the ReverseString function | |
| output := ReverseString(input) | |
| // Print the result | |
| fmt.Println(output) | |
| } | |
| } | |
| func main() { | |
| // Read input from standard input | |
| scanner := bufio.NewScanner(os.Stdin) | |
| if scanner.Scan() { | |
| input := scanner.Text() | |
| // Call the ReverseString function | |
| output := ReverseString(input) | |
| // Print the result | |
| fmt.Println(output) | |
| } | |
| // Check for scanner errors | |
| if err := scanner.Err(); err != nil { | |
| fmt.Fprintf(os.Stderr, "Error reading input: %v\n", err) | |
| os.Exit(1) | |
| } | |
| } |
🤖 Prompt for AI Agents
In challenge-2/submissions/nasseredine/solution-template.go around lines 11 to
23, the main function calls scanner.Scan() but does not check scanner.Err() when
Scan returns false; update the function to check scanner.Err() after scanning
and handle read errors by printing an error message to stderr (for example via
fmt.Fprintln(os.Stderr, ...)) and exiting with a non-zero status, while
preserving normal behavior when EOF is reached; ensure any error path
returns/exit after reporting so the program does not continue silently.
| // ReverseString returns the reversed string of s. | ||
| func ReverseString(s string) string { | ||
| // Don't reinvent the wheel! | ||
| return reverse.String(s) | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion | 🟠 Major
Implement string reversal locally instead of using example dependency.
Since the external dependency should be avoided (see previous comment), implement the reversal directly. Here's a Unicode-aware implementation:
// ReverseString returns the reversed string of s.
func ReverseString(s string) string {
- // Don't reinvent the wheel!
- return reverse.String(s)
+ // Convert to runes for proper Unicode handling
+ runes := []rune(s)
+ for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
+ runes[i], runes[j] = runes[j], runes[i]
+ }
+ return string(runes)
}This handles Unicode code points correctly (e.g., "Hello, 世界" → "界世 ,olleH").
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| // ReverseString returns the reversed string of s. | |
| func ReverseString(s string) string { | |
| // Don't reinvent the wheel! | |
| return reverse.String(s) | |
| } | |
| // ReverseString returns the reversed string of s. | |
| func ReverseString(s string) string { | |
| // Convert to runes for proper Unicode handling | |
| runes := []rune(s) | |
| for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 { | |
| runes[i], runes[j] = runes[j], runes[i] | |
| } | |
| return string(runes) | |
| } |
🤖 Prompt for AI Agents
In challenge-2/submissions/nasseredine/solution-template.go around lines 25 to
29, the function ReverseString currently delegates to an external example
dependency (reverse.String); replace that call with a local, Unicode-aware
implementation: convert the input string to a slice of runes, reverse the rune
slice in-place (swap runes from ends toward center), and return a new string
from the reversed rune slice; remove the dependency usage and ensure the
function handles multi-byte Unicode characters correctly (e.g., "Hello, 世界" →
"界世 ,olleH").
1 participant
Challenge 2 Solution
Submitted by: @nasseredine
Challenge: Challenge 2
Description
This PR contains my solution for Challenge 2.
Changes
challenge-2/submissions/nasseredine/solution-template.goTesting
Thank you for reviewing my submission! 🚀