Logical operators in Go - Mini Project: Build & Apply

Logical operators

📖 Scenario: You are helping a store manager decide which products to restock based on their sales and stock levels.

🎯 Goal: Build a Go program that uses logical operators to find products that need restocking.

📋 What You'll Learn

Create a map called products with product names as keys and their stock counts as values.

Create a map called sales with product names as keys and their sales counts as values.

Create a variable called restockThreshold to set the minimum stock level before restocking.

Use a for loop with variables product and stock to iterate over products.

Inside the loop, use an if statement with logical operators && and || to check if a product's stock is below restockThreshold or if sales are high.

Print the names of products that need restocking.

💡 Why This Matters

🌍 Real World

Stores often need to decide which products to order more of based on current stock and sales trends.

💼 Career

Understanding logical operators and data structures like maps is essential for roles in software development, data analysis, and inventory management systems.

1

Create the products map

Create a map called products with these exact entries: "Apples": 50, "Bananas": 20, "Cherries": 0, "Dates": 15.

Go

var products = map[string]int{
    // Your code here
}

Hint

Use map[string]int to create a map with string keys and int values.

2

Create the sales map and restock threshold

Create a map called sales with these exact entries: "Apples": 30, "Bananas": 50, "Cherries": 5, "Dates": 10. Also create an integer variable called restockThreshold and set it to 20.

Go

package main

import "fmt"

func main() {
    products := map[string]int{"Apples": 50, "Bananas": 20, "Cherries": 0, "Dates": 15}
    // Your code here
}

Hint

Use the same map syntax as before for sales. Use := to create restockThreshold.

3

Use logical operators to find products to restock

Use a for loop with variables product and stock to iterate over products. Inside the loop, use an if statement with logical operators && and || to check if stock is less than restockThreshold or if sales[product] is greater than 30. If so, add the product to a slice called toRestock.

Go

package main

import "fmt"

func main() {
    products := map[string]int{"Apples": 50, "Bananas": 20, "Cherries": 0, "Dates": 15}
    sales := map[string]int{"Apples": 30, "Bananas": 50, "Cherries": 5, "Dates": 10}
    restockThreshold := 20

    // Your code here
}

Hint

Use range to loop over the map. Use append to add to the slice.

4

Print the products to restock

Write a for loop with variable product to iterate over toRestock and print each product.

Go

package main

import "fmt"

func main() {
    products := map[string]int{"Apples": 50, "Bananas": 20, "Cherries": 0, "Dates": 15}
    sales := map[string]int{"Apples": 30, "Bananas": 50, "Cherries": 5, "Dates": 10}
    restockThreshold := 20

    toRestock := []string{}
    for product, stock := range products {
        if stock  30 {
            toRestock = append(toRestock, product)
        }
    }

    // Your code here
}

Hint

Use for _, product := range toRestock to loop over the slice and fmt.Println(product) to print.

Practice

1. Which logical operator in Go means AND and returns true only if both conditions are true?

easy

A. !

B. ||

C. &

D. &&

Solution

1. Step 1: Understand the meaning of logical AND

   The AND operator returns true only when both conditions it connects are true.

2. Step 2: Identify Go's AND operator

   In Go, the AND operator is written as &&, which matches the description.

3. Final Answer:

   && -> Option D

4. Quick Check:

   AND = && [OK]

Hint: AND is &&, OR is ||, NOT is ! [OK]

Common Mistakes:

• Confusing & (bitwise AND) with && (logical AND)
• Mixing OR (||) with AND (&&)
• Using ! as AND operator

2. Which of the following is the correct syntax for the logical NOT operator in Go?

easy

A. not x

B. !x

C. ~x

D. x!

Solution

1. Step 1: Recall Go syntax for logical NOT

   In Go, the logical NOT operator is a single exclamation mark placed before the variable or expression.

2. Step 2: Match options with correct syntax

   !x uses !x, which is the correct syntax for NOT in Go.

3. Final Answer:

   !x -> Option B

4. Quick Check:

   NOT = ! [OK]

Hint: NOT always uses ! before the condition [OK]

Common Mistakes:

• Writing 'not x' like in some other languages
• Using ~ which is bitwise NOT, not logical NOT
• Placing ! after the variable

3. What is the output of this Go code snippet?

package main
import "fmt"
func main() {
    a := true
    b := false
    fmt.Println(a && !b || b)
}

medium

A. true

B. false

C. Syntax error

D. Compilation error

Solution

1. Step 1: Evaluate !b

   b is false, so !b is true.

2. Step 2: Evaluate a && !b

   a is true and !b is true, so a && !b is true.

3. Step 3: Evaluate (a && !b) || b

   true || false is true.

4. Final Answer:

   true -> Option A

5. Quick Check:

   True AND NOT False OR False = True [OK]

Hint: Evaluate NOT first, then AND, then OR [OK]

Common Mistakes:

• Evaluating OR before AND
• Forgetting to negate b
• Assuming false || true is false

4. Identify the error in this Go code snippet:

package main
import "fmt"
func main() {
    x := true
    y := false
    if x & y {
        fmt.Println("Both true")
    }
}

medium

A. Using & instead of && in if condition

B. Missing parentheses around condition

C. fmt.Println syntax error

D. Variable declaration error

Solution

1. Step 1: Check logical operators in if condition

   The code uses & which is bitwise AND, not logical AND.

2. Step 2: Identify correct operator for boolean logic

   Logical AND in Go is &&, so & causes a type error here.

3. Final Answer:

   Using & instead of && in if condition -> Option A

4. Quick Check:

   Logical AND needs &&, not & [OK]

Hint: Use && for logical AND, & is bitwise [OK]

Common Mistakes:

• Using & instead of && for booleans
• Assuming & works like && in conditions
• Ignoring compiler error messages

5. Given a variable score (int), which condition correctly checks if score is between 50 and 100 inclusive using logical operators in Go?

hard

A. score >= 50 || score <= 100

B. score > 50 && score < 100

C. score >= 50 && score <= 100

D. score > 50 || score < 100

Solution

1. Step 1: Understand the range condition

   We want score to be at least 50 and at most 100, so both conditions must be true.

2. Step 2: Choose correct logical operator

   AND (&&) combines conditions that both must be true; OR (||) would allow values outside the range.

3. Step 3: Check inclusivity

   Using >= and <= includes 50 and 100 themselves.

4. Final Answer:

   score >= 50 && score <= 100 -> Option C

5. Quick Check:

   Between means AND, not OR [OK]

Hint: Use && to combine conditions that both must be true [OK]

Common Mistakes:

• Using || which allows values outside range
• Using > and < excludes boundary values
• Confusing AND and OR logic