Operators in Go

# CHAPTER 5

Operators in Go #

1. Introduction #

2. Learning Objectives #

• Perform math using Arithmetic Operators.

• Compare variables using Comparison Operators.

• Combine conditions using Logical Operators.

• Update variables efficiently using Assignment Operators.

• Understand the basics of Bitwise Operators.

3. Arithmetic Operators #

Important Note on Division: If you divide two integers, Go truncates the decimal. 5 / 2 results in 2. To get 2.5, at least one number must be a float64: 5.0 / 2.0.

4. Assignment Operators #

5. Comparison Operators #

6. Logical Operators #

package main
import "fmt"

func main() {
    age := 25
    hasLicense := true

    // Using Logical AND
    canRentCar := (age >= 25) && hasLicense
    fmt.Println("Can rent a car:", canRentCar) // true
}

7. Bitwise Operators (Advanced) #

• & (AND)

• | (OR)

• ^ (XOR)

• << (Left Shift)

• >> (Right Shift)

*Note: As a beginner backend developer, you rarely use bitwise operators. Focus on Arithmetic, Comparison, and Logical operators first!*

8. Strict Typing with Operators (Common Mistake) #

func main() {
    var a int = 10
    var b float64 = 5.5

    // fmt.Println(a + b) // ERROR: invalid operation: a + b (mismatched types int and float64)
    
    // You MUST convert 'a' to a float64 explicitly
    fmt.Println(float64(a) + b) // Valid: 15.5
}

9. Best Practices #

• Parentheses for clarity: While a + b * c works because of the order of operations, a + (b * c) is instantly readable to other developers.

• No Pre-increment: In C/C++, you can write ++x or x++. Go *only* allows postfix increments (x++), and it is a statement, not an expression. You cannot write y = x++. This design choice eliminates thousands of confusing bugs found in C.

10. Exercises #

1. 1. Create a variable score := 100. Use the += operator to add 50 to it, then print it.

1. 2. Create two variables: x := 10 and y := 3. Print the result of x % y and explain what the output means.

11. MCQs with Answers & Explanations #

Q10. Can you use x++ inside an assignment like y = x++ in Go? a) Yes b) No Answer: b) No. *Explanation: x++ is a statement in Go, not an expression that returns a value.*

12. Interview Preparation #

1. 1. Why does Go prevent operations between an int and a float64?

1. 2. Explain the difference between == and =.

Common Pitfall: Forgetting that integer division drops the decimal. If you are calculating an average, always convert the integers to float64 before dividing, otherwise your average will be inaccurate.

13. Summary #

14. Next Chapter Recommendation #