Relational operators in Go - Mini Project: Build & Apply

Relational Operators in Go

📖 Scenario: You are creating a simple program to compare ages of two friends to see who is older.

🎯 Goal: Build a Go program that uses relational operators to compare two age values and prints the comparison results.

📋 What You'll Learn

Create two integer variables with exact values

Create a boolean variable to store a comparison result

Use relational operators to compare the two ages

Print the results of the comparisons

💡 Why This Matters

🌍 Real World

Comparing values is common in programs that make decisions, like checking ages, prices, or scores.

💼 Career

Understanding relational operators is essential for any programming job because they help control the flow of logic.

1

Create age variables

Create two integer variables called ageAlice and ageBob with values 25 and 30 respectively.

Go

package main

func main() {
    // Create ageAlice and ageBob variables
    // Your code here
}

Hint

Use := to declare and assign variables in Go.

2

Create a boolean variable for comparison

Create a boolean variable called isAliceOlder and set it to the result of comparing if ageAlice is greater than ageBob using the relational operator >.

Go

package main

func main() {
    ageAlice := 25
    ageBob := 30
    // Create isAliceOlder variable with comparison
    // Your code here
}

Hint

Use the > operator to check if one number is greater than another.

3

Compare ages with other relational operators

Create three more boolean variables: isAliceYounger for ageAlice < ageBob, isSameAge for ageAlice == ageBob, and isNotSameAge for ageAlice != ageBob.

Go

package main

func main() {
    ageAlice := 25
    ageBob := 30
    isAliceOlder := ageAlice > ageBob
    // Create isAliceYounger, isSameAge, and isNotSameAge variables
    // Your code here
}

Hint

Use <, ==, and != operators for less than, equal to, and not equal to comparisons.

4

Print the comparison results

Use fmt.Println to print the values of isAliceOlder, isAliceYounger, isSameAge, and isNotSameAge each on a new line. Remember to import the fmt package.

Go

package main

import "fmt"

func main() {
    ageAlice := 25
    ageBob := 30
    isAliceOlder := ageAlice > ageBob
    isAliceYounger := ageAlice < ageBob
    isSameAge := ageAlice == ageBob
    isNotSameAge := ageAlice != ageBob
    // Print all boolean variables
    // Your code here
}

Hint

Use fmt.Println(variable) to print each variable on its own line.

Practice

1. Which of the following relational operators in Go checks if two values are equal?

easy

A. >

B. !=

C. ==

D. <=

Solution

1. Step 1: Understand the meaning of relational operators

   Relational operators compare two values and return true or false based on the comparison.

2. Step 2: Identify the operator for equality

   The operator '==' checks if two values are equal in Go.

3. Final Answer:

   == -> Option C

4. Quick Check:

   Equality operator = == [OK]

Hint: Remember: double equals (==) means equal in Go [OK]

Common Mistakes:

• Confusing '=' (assignment) with '==' (equality)
• Using '!=' for equality check
• Thinking '>' means equal

2. Which of the following is the correct syntax to check if variable a is not equal to variable b in Go?

easy

A. a !== b

B. a <> b

C. a =! b

D. a != b

Solution

1. Step 1: Recall Go syntax for not equal operator

   In Go, the not equal operator is written as '!='.

2. Step 2: Match the syntax with the options

   a != b uses 'a != b', which is correct syntax for not equal in Go.

3. Final Answer:

   a != b -> Option D

4. Quick Check:

   Not equal operator = != [OK]

Hint: Not equal in Go is always '!=' not '<>' or '!==' [OK]

Common Mistakes:

• Using '<>' which is not valid in Go
• Swapping '=' and '!' to '=!'
• Using JavaScript style '!==' which is invalid in Go

3. What will be the output of the following Go code?

package main
import "fmt"
func main() {
    x := 10
    y := 20
    fmt.Println(x > y)
}

medium

A. false

B. 10

C. true

D. Compilation error

Solution

1. Step 1: Understand the comparison x > y

   Variable x is 10 and y is 20. The expression checks if 10 is greater than 20.

2. Step 2: Evaluate the expression

   Since 10 is not greater than 20, the expression evaluates to false.

3. Final Answer:

   false -> Option A

4. Quick Check:

   10 > 20 = false [OK]

Hint: Compare values carefully; 10 > 20 is false [OK]

Common Mistakes:

• Assuming 10 > 20 is true
• Confusing output with variable values
• Expecting a number instead of boolean

4. Identify the error in the following Go code snippet:

package main
import "fmt"
func main() {
    a := 5
    b := 10
    if a = b {
        fmt.Println("Equal")
    }
}

medium

A. Variables 'a' and 'b' are not declared properly

B. The '=' operator is used instead of '==' in the if condition

C. Missing parentheses around the if condition

D. fmt.Println syntax is incorrect

Solution

1. Step 1: Check the if condition syntax

   The condition uses 'a = b' which is an assignment, not a comparison.

2. Step 2: Correct the operator for comparison

   To compare values, '==' must be used instead of '='.

3. Final Answer:

   The '=' operator is used instead of '==' in the if condition -> Option B

4. Quick Check:

   Use '==' for comparison, not '=' [OK]

Hint: Use '==' to compare, '=' only assigns [OK]

Common Mistakes:

• Using '=' instead of '==' in conditions
• Thinking parentheses are mandatory in Go if
• Assuming fmt.Println syntax is wrong

5. Given the following Go code, what will be the output?

package main
import "fmt"
func main() {
    a := 15
    b := 15
    c := 20
    result := (a == b) && (c > b)
    fmt.Println(result)
}

hard

A. true

B. false

C. Compilation error

D. 15

Solution

1. Step 1: Evaluate the first comparison (a == b)

   Both a and b are 15, so (a == b) is true.

2. Step 2: Evaluate the second comparison (c > b)

   c is 20 and b is 15, so (c > b) is true.

3. Step 3: Combine with logical AND

   Both conditions are true, so true && true is true.

4. Final Answer:

   true -> Option A

5. Quick Check:

   (15 == 15) && (20 > 15) = true [OK]

Hint: Both conditions true? Result is true [OK]

Common Mistakes:

• Confusing && with || operator
• Thinking one true means overall false
• Expecting numeric output instead of boolean