Relational operators in Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are relational operators in Go?

Relational operators compare two values and return a boolean result: true or false. They help decide if one value is equal to, greater than, or less than another.

beginner

List the common relational operators in Go.

== (equal to), != (not equal to), < (less than), <= (less than or equal to), > (greater than), >= (greater than or equal to).

beginner

What does the expression '5 < 10' return in Go?

It returns true because 5 is less than 10.

intermediate

Can relational operators be used with strings in Go?

Yes, strings can be compared using relational operators like == and != to check equality or inequality. Also, < and > compare strings lexicographically (dictionary order).

beginner

What is the result of '7 != 7' in Go?

It returns false because 7 is equal to 7, so they are not different.

Which operator checks if two values are NOT equal in Go?

A <=

B ==

C >

D !=

The '!=' operator returns true if the two values are different.

What does the expression '10 >= 5' evaluate to?

A false

B nil

C true

D error

10 is greater than or equal to 5, so the expression is true.

Which relational operator means 'less than or equal to'?

A ==

B <=

C >=

D !=

The '<=' operator means less than or equal to.

Can you use relational operators to compare two strings in Go?

A Yes, including == and <

B No, only numbers can be compared

C Only == can be used

D Only != can be used

Go allows comparing strings with ==, !=, <, >, <=, and >=.

What is the result of '3 == 4' in Go?

A false

B true

C 3

D 4

3 is not equal to 4, so the expression returns false.

Explain what relational operators do in Go and give examples.

Think about how you compare numbers or words in real life.

Describe how you can compare strings using relational operators in Go.

Imagine checking if two words are the same or which comes first alphabetically.

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