Handling errors in Go - Mini Project: Build & Apply

Handling errors

📖 Scenario: You are writing a small program that divides numbers. Sometimes, the divisor might be zero, which causes an error. You want to handle this error properly so the program does not crash and shows a friendly message.

🎯 Goal: Build a Go program that divides two numbers and handles the error when dividing by zero.

📋 What You'll Learn

Create two variables for dividend and divisor

Create a function that divides two numbers and returns an error if divisor is zero

Call the function and handle the error using an if statement

Print the result if no error, or print the error message

💡 Why This Matters

🌍 Real World

Handling errors is important in real programs to avoid crashes and provide clear messages to users.

💼 Career

Error handling is a fundamental skill for software developers to write reliable and user-friendly applications.

1

Create variables for dividend and divisor

Create two variables called dividend and divisor with values 10 and 0 respectively.

Go

var dividend int = 10
var divisor int = 0
// Your code here

Hint

Use var keyword to declare variables with their types and values.

2

Create a divide function that returns error

Create a function called divide that takes two int parameters named a and b. It returns two values: int and error. If b is zero, return zero and an error created with fmt.Errorf("cannot divide by zero"). Otherwise, return the division result and nil error.

Go

package main

import "fmt"

func divide(a int, b int) (int, error) {
    // Your code here
}

func main() {
    var dividend int = 10
    var divisor int = 0
}

Hint

Use fmt.Errorf to create an error message.

3

Call divide function and handle error

In main, call divide(dividend, divisor) and assign the results to variables result and err. Use an if statement to check if err is not nil. If so, print the error message using fmt.Println(err). Otherwise, print the result using fmt.Println(result).

Go

package main

import "fmt"

func divide(a int, b int) (int, error) {
    if b == 0 {
        return 0, fmt.Errorf("cannot divide by zero")
    }
    return a / b, nil
}

func main() {
    var dividend int = 10
    var divisor int = 0

    // Your code here
}

Hint

Use if err != nil to check for errors.

4

Print the final output

Run the program and observe the output. It should print the error message cannot divide by zero because the divisor is zero.

Go

package main

import "fmt"

func divide(a int, b int) (int, error) {
    if b == 0 {
        return 0, fmt.Errorf("cannot divide by zero")
    }
    return a / b, nil
}

func main() {
    var dividend int = 10
    var divisor int = 0

    result, err := divide(dividend, divisor)
    if err != nil {
        fmt.Println(err)
    } else {
        fmt.Println(result)
    }

    // Your code here
}

Hint

The program should print the error message because dividing by zero is not allowed.