GOin 45 days

Week 1 · project

Word-frequency CLI

Build a tested command-line tool from the foundations in Week 1.

projectclitext

Today’s outcome

  • Explain the central idea in your own words.
  • Predict the behavior of a small example before running it.
  • Finish the acceptance checklist with the real Go toolchain.

Turn the week into a program

Go rewards a small number of ideas applied consistently: keep ownership clear, make failure explicit, and prefer code whose behavior is easy to test. Today’s focus is word-frequency cli. Begin by connecting it to code you already understand, then isolate one behavior at a time.

Build a tested command-line tool from the foundations in Week 1. Read the example slowly. Predict the result before running it, name the rule that produced it, and change one input. That short loop turns documentation into working knowledge.

Gotcha — familiarity is not recall.

If an example looks obvious, close it and reproduce it from memory. The gap between recognizing code and writing it is where the useful practice lives.

Use the toolchain as feedback

Format early, run focused tests, and read the complete failure before editing. Go’s compiler and standard tools are part of the learning environment. A short, repeatable loop beats a large untested change.

Try · predict before you run

example 1.goOpen Playground ↗
package main

import "fmt"

func main() {
	fmt.Println("Word-frequency CLI")
}
example 2.goOpen Playground ↗
// Make the smallest behavior observable.
// Then add one edge case and run it again.
example 3.goOpen Playground ↗
// Local workflow
// gofmt -w .
// go test ./...
// go vet ./...

Check the model

Quick review

Score 70% or higher. Your best score is saved.

1. What is the main goal of today’s Word-frequency CLI lesson?
2. Which practice best supports clear project code?
3. What should you do before claiming a program works?
4. What is the most useful response to a failing test?
5. Which design usually makes Go code easier to maintain?
6. How should you approach the Word-frequency CLI coding task?
7. Why does the course include a reflection note?
8. When should you use the Go documentation?

Make it yours

Project checklist

Word counting

warmup

Work locally, run go test ./..., and mark this when the corresponding checks pass.

Hint

Write the smallest example first. Use its result to decide the next case.

Open Playground ↗

Stable top-N output

core

Work locally, run go test ./..., and mark this when the corresponding checks pass.

Hint

Write the smallest example first. Use its result to decide the next case.

Open Playground ↗

Flags and stopwords

stretch

Work locally, run go test ./..., and mark this when the corresponding checks pass.

Hint

Write the smallest example first. Use its result to decide the next case.

Open Playground ↗

Reflect

What clicked? What still feels fuzzy?