If statement in Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of an if statement in Go?

An if statement lets the program decide to run some code only if a condition is true. It's like choosing a path based on a yes/no question.

beginner

How do you write a simple if statement in Go?

You write if condition { /* code to run if true */ }. The condition follows directly after if without parentheses, and the code to run is inside curly braces.

beginner

Can you use an if statement without an else in Go?

Yes! You can run code only when the condition is true and do nothing if it is false. The else part is optional.

beginner

What happens if the if condition is false and there is no else block?

The program skips the code inside the if block and continues running the rest of the program.

beginner

How do you write an if-else statement in Go?

You write if condition { /* code if true */ } else { /* code if false */ }. This runs one block or the other depending on the condition.

What does an if statement do in Go?

A Runs code only if a condition is true

B Runs code repeatedly

C Defines a function

D Declares a variable

An if statement checks a condition and runs code only when it is true.

Which symbol is used to start the code block after an if condition in Go?

A [ ]

B ( )

C { }

D < >

Curly braces { } are used to group the code that runs if the condition is true.

Is the else part mandatory after an if in Go?

A No, it's optional

B Only inside loops

C Only if the condition is false

D Yes, always

The else block is optional; you can have just an if statement.

What happens if the if condition is false and there is no else?

A Program crashes

B Code inside <code>if</code> runs anyway

C Program asks for input

D Code inside <code>if</code> is skipped

If the condition is false and no else exists, the code inside if is skipped.

How do you write an if-else statement in Go?

A if (condition) then { } else { }

B if condition { } else { }

C if condition: { } else: { }

D if condition -> { } else -> { }

The correct syntax is if condition { } else { } without extra words or symbols.

Explain how an if statement controls the flow of a Go program.

Think about how you decide to do something only if a condition is met.

Write the syntax of a simple if statement in Go and describe each part.

Remember the shape of the code with braces and the condition.

Practice

1. What does an if statement do in Go?

easy

A. It runs code only if a condition is true.

B. It repeats code multiple times.

C. It stores data in a variable.

D. It defines a new function.

Solution

1. Step 1: Understand the purpose of an if statement

   An if statement checks a condition and runs code only when that condition is true.

2. Step 2: Compare options with the if statement behavior

   Only "It runs code only if a condition is true." describes running code based on a condition being true.

3. Final Answer:

   It runs code only if a condition is true. -> Option A

4. Quick Check:

   If statement = runs code if true [OK]

Hint: If checks true/false to decide running code [OK]

Common Mistakes:

• Confusing if with loops
• Thinking if stores data
• Mixing if with function definitions

2. Which of these is the correct syntax for an if statement in Go?

easy

A. if (x > 10) then { fmt.Println("Big") }

B. if x > 10 { fmt.Println("Big") }

C. if x > 10: fmt.Println("Big")

D. if x > 10 { fmt.Println("Big") else }

Solution

1. Step 1: Recall Go if statement syntax

   Go uses if condition { code } without parentheses or 'then'.

2. Step 2: Check each option

   if x > 10 { fmt.Println("Big") } matches Go syntax exactly. Options A, C, and D have syntax errors.

3. Final Answer:

   if x > 10 { fmt.Println("Big") } -> Option B

4. Quick Check:

   Go if syntax = if condition { } [OK]

Hint: Go if uses braces, no 'then' or colons [OK]

Common Mistakes:

• Adding 'then' keyword
• Using parentheses around condition
• Using colon instead of braces

3. What is the output of this Go code?

package main
import "fmt"
func main() {
  x := 5
  if x > 3 {
    fmt.Println("Yes")
  } else {
    fmt.Println("No")
  }
}

medium

A. Syntax error

B. No

C. 5

D. Yes

Solution

1. Step 1: Check the condition in the if statement

   The variable x is 5, and the condition is x > 3, which is true.

2. Step 2: Determine which block runs

   Since the condition is true, the code inside the if block runs, printing "Yes".

3. Final Answer:

   Yes -> Option D

4. Quick Check:

   x=5 > 3 is true, prints "Yes" [OK]

Hint: If condition true runs if-block, else runs else-block [OK]

Common Mistakes:

• Confusing which block runs
• Thinking it prints the variable
• Assuming syntax error due to else

4. Find the error in this Go code:

package main
import "fmt"
func main() {
  x := 10
  if x > 5
    fmt.Println("Big")
}

medium

A. Variable x not declared

B. Missing semicolon after x := 10

C. Missing braces { } after if condition

D. Wrong import statement

Solution

1. Step 1: Check if statement syntax

   In Go, the if condition must be followed by braces { } to group the code.

2. Step 2: Identify the missing part

   The code after if lacks braces, causing a syntax error.

3. Final Answer:

   Missing braces { } after if condition -> Option C

4. Quick Check:

   If needs braces { } after condition [OK]

Hint: Always use braces { } after if condition [OK]

Common Mistakes:

• Omitting braces after if
• Adding unnecessary semicolons
• Misunderstanding import errors

5. You want to print "Positive", "Zero", or "Negative" based on an integer variable n. Which code correctly uses if statements to do this?

hard

A. if n > 0 { fmt.Println("Positive") } else if n == 0 { fmt.Println("Zero") } else { fmt.Println("Negative") }

B. if n > 0 { fmt.Println("Positive") } if n == 0 { fmt.Println("Zero") } else { fmt.Println("Negative") }

C. if n > 0 { fmt.Println("Positive") } else if n <= 0 { fmt.Println("Negative") } else { fmt.Println("Zero") }

D. if n >= 0 { fmt.Println("Positive") } else if n == 0 { fmt.Println("Zero") } else { fmt.Println("Negative") }

Solution

1. Step 1: Understand the conditions for each case

   Positive means n > 0, zero means n == 0, negative means n < 0.

2. Step 2: Check each option's logic

   if n > 0 { fmt.Println("Positive") } else if n == 0 { fmt.Println("Zero") } else { fmt.Println("Negative") } correctly checks n > 0, then n == 0, else negative. if n > 0 { fmt.Println("Positive") } if n == 0 { fmt.Println("Zero") } else { fmt.Println("Negative") } has two separate ifs causing multiple prints. if n > 0 { fmt.Println("Positive") } else if n <= 0 { fmt.Println("Negative") } else { fmt.Println("Zero") } swaps zero and negative logic. if n >= 0 { fmt.Println("Positive") } else if n == 0 { fmt.Println("Zero") } else { fmt.Println("Negative") } wrongly treats n >= 0 as positive.

3. Final Answer:

   if n > 0 { fmt.Println("Positive") } else if n == 0 { fmt.Println("Zero") } else { fmt.Println("Negative") } -> Option A

4. Quick Check:

   Correct if-else chain matches conditions [OK]

Hint: Use else if to check exclusive conditions in order [OK]

Common Mistakes:

• Using multiple ifs causing multiple outputs
• Mixing condition order
• Wrong comparison operators