Why conditional logic is needed in Go

Introduction

Conditional logic helps a program make decisions. It lets the program choose what to do based on different situations.

When you want to check if a user entered the correct password.

When you want to give a discount only if the customer buys more than 5 items.

When you want to show a message only if it is morning.

When you want to stop a game if the player loses all lives.

When you want to perform different actions based on user input.

Syntax

Go

if condition {
    // code to run if condition is true
} else {
    // code to run if condition is false
}

The if keyword checks a condition.

The else part runs if the if condition is false.

Examples

This checks if age is 18 or more. It prints a message based on that.

Go

if age >= 18 {
    fmt.Println("You can vote.")
} else {
    fmt.Println("You are too young to vote.")
}

This runs code only if the score is above 90.

Go

if score > 90 {
    fmt.Println("Great job!")
}

Sample Program

This program checks the temperature. It prints if it is hot or not.

Go

package main

import "fmt"

func main() {
    temperature := 30
    if temperature > 25 {
        fmt.Println("It's hot outside.")
    } else {
        fmt.Println("It's not hot today.")
    }
}

Important Notes

Always make sure your conditions are clear and simple.

You can use multiple if and else if to check many conditions.

Summary

Conditional logic lets programs make choices.

Use if and else to run code based on conditions.

This helps programs react differently in different situations.

Practice

1. Why do we use conditional logic like if statements in Go programs?

easy

A. To repeat code multiple times automatically

B. To make decisions and run different code based on conditions

C. To store data in variables

D. To define new functions

Solution

1. Step 1: Understand the purpose of conditional logic

   Conditional logic allows a program to choose between different actions depending on whether a condition is true or false.

2. Step 2: Compare with other programming concepts

   Loops repeat code, variables store data, and functions define reusable code blocks, but only conditionals make decisions.

3. Final Answer:

   To make decisions and run different code based on conditions -> Option B

4. Quick Check:

   Conditional logic = decision making [OK]

Hint: Remember: if means 'choose this if true' [OK]

Common Mistakes:

• Confusing conditionals with loops
• Thinking variables make decisions
• Mixing functions with conditionals

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

easy

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

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

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

D. if x > 10 print("Big")

Solution

1. Step 1: Recall Go's if statement syntax

   In Go, conditions are written without parentheses, and the code block is inside curly braces.

2. Step 2: Check each option

   if x > 10 { fmt.Println("Big") } matches Go syntax exactly. Options A, B, and D use syntax from other languages or are incorrect.

3. Final Answer:

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

4. Quick Check:

   Go if syntax uses braces, no parentheses [OK]

Hint: Go if uses braces {} without parentheses () [OK]

Common Mistakes:

• Adding parentheses around conditions
• Using 'then' keyword
• Omitting braces for code blocks

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

package main
import "fmt"
func main() {
  x := 5
  if x > 3 {
    fmt.Println("Greater")
  } else {
    fmt.Println("Smaller")
  }
}

medium

A. Greater

B. Smaller

C. 5

D. No output

Solution

1. Step 1: Evaluate the condition x > 3

   The variable x is 5, which is greater than 3, so the condition is true.

2. Step 2: Determine which branch runs

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

3. Final Answer:

   Greater -> Option A

4. Quick Check:

   5 > 3 is true, so prints "Greater" [OK]

Hint: Check if condition is true or false to pick output [OK]

Common Mistakes:

• Choosing else output when condition is true
• Confusing printed value with variable value
• Ignoring else block

4. Find the error in this Go code snippet:

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

medium

A. The '=' should be '==' in the if condition

B. Missing curly braces around if block

C. fmt.Println is used incorrectly

D. Variable x is not declared

Solution

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

   The code uses 'x = 5' which is an assignment, not a comparison.

2. Step 2: Correct the condition operator

   To compare values, Go requires '==' instead of '=' in conditions.

3. Final Answer:

   The '=' should be '==' in the if condition -> Option A

4. Quick Check:

   Use '==' to compare, '=' assigns [OK]

Hint: Use '==' for comparison, '=' for assignment [OK]

Common Mistakes:

• Using '=' instead of '==' in conditions
• Forgetting braces after if
• Misusing print function

5. You want to write a Go program that prints "Adult" if age is 18 or more, and "Minor" otherwise. Which code correctly uses conditional logic to do this?

hard

A. if age < 18 { fmt.Println("Adult") } else { fmt.Println("Minor") }

B. if age > 18 { fmt.Println("Adult") } else { fmt.Println("Minor") }

C. if age = 18 { fmt.Println("Adult") } else { fmt.Println("Minor") }

D. if age >= 18 { fmt.Println("Adult") } else { fmt.Println("Minor") }

Solution

1. Step 1: Understand the age condition

   We want to print "Adult" if age is 18 or more, so the condition should be age >= 18.

2. Step 2: Check each option's condition

   if age >= 18 { fmt.Println("Adult") } else { fmt.Println("Minor") } uses age >= 18 correctly. if age > 18 { fmt.Println("Adult") } else { fmt.Println("Minor") } excludes age 18. if age = 18 { fmt.Println("Adult") } else { fmt.Println("Minor") } uses '=' which is assignment, not comparison. if age < 18 { fmt.Println("Adult") } else { fmt.Println("Minor") } reverses logic.

3. Final Answer:

   if age >= 18 { fmt.Println("Adult") } else { fmt.Println("Minor") } -> Option D

4. Quick Check:

   Use '>=' to include 18 as adult [OK]

Hint: Use '>=' to include boundary values in conditions [OK]

Common Mistakes:

• Using '=' instead of '=='
• Using '>' instead of '>='
• Reversing if and else blocks