Basic input concepts in Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What package is commonly used in Go to read input from the user?

The fmt package is commonly used to read input from the user in Go, especially with functions like fmt.Scan and fmt.Scanln.

intermediate

How does fmt.Scanln differ from fmt.Scan in Go?

fmt.Scanln reads input until a newline is encountered, while fmt.Scan reads input separated by spaces and stops at a newline or space.

beginner

Write a simple Go code snippet to read a string input from the user.

```go
package main

import "fmt"

func main() {
    var name string
    fmt.Print("Enter your name: ")
    fmt.Scanln(&name)
    fmt.Println("Hello,", name)
}
```

beginner

Why do we use the ampersand (&) before a variable when reading input in Go?

The ampersand (&) is used to pass the memory address of the variable to the input function, so the function can store the input value directly into that variable.

intermediate

What happens if the user inputs a different data type than expected in Go's fmt.Scanln?

If the input type does not match the variable type, fmt.Scanln will return an error and the variable may not be set correctly.

Which Go function reads input until the user presses Enter?

A fmt.Scanln

B fmt.Println

C fmt.Printf

D fmt.Scanf

fmt.Scanln reads input until a newline (Enter) is pressed.

What does the & symbol do when used in fmt.Scanln(&variable)?

A Prints the variable

B Passes the variable's address to store input

C Declares a new variable

D Converts variable to string

The & symbol passes the memory address of the variable so input can be stored there.

Which package must be imported to use fmt.Scanln?

A os

B io

C fmt

D bufio

The fmt package provides Scanln for input.

If you want to read multiple values separated by spaces, which function is suitable?

A fmt.Scanln

B fmt.Sprintf

C fmt.Println

D fmt.Scan

fmt.Scan reads multiple space-separated inputs.

What happens if input type does not match the variable type in fmt.Scanln?

A An error is returned and variable may not be set

B Input is automatically converted

C Program crashes immediately

D Input is ignored silently

Mismatched types cause an error and the variable may not be assigned.

Explain how to read a string input from the user in Go using fmt.Scanln.

Think about how you ask a friend for their name and store it.

Describe why the ampersand (&) is necessary when reading input into a variable in Go.

Imagine giving someone your mailbox address so they can put a letter inside.