Explain the use of Go's conditional statements (if, switch, etc.) for controlling flow of execution?

Question

Jayant Kumar · Accepted Answer

Table of Contents
Introduction
Conditional statements are fundamental in programming languages for controlling the flow of execution based on specific conditions. In Go, the primary conditional statements are if, else if, else, and switch. These statements enable developers to direct the program's execution path according to the results of logical expressions.
If Statement
Definition
The if statement in Go is used to execute a block of code if a specified condition evaluates to true.
Syntax
if condition {
    // Code to execute if condition is true
}

Example
x := 10
if x > 5 {
    fmt.Println("x is greater than 5")
}

In this example, the condition x > 5 evaluates to true, so the code inside the if block is executed, and the output is:
x is greater than 5

If-Else Statement
Definition
The if-else statement allows you to execute one block of code if the condition is true and another block if the condition is false.
Syntax
if condition {
    // Code to execute if condition is true
} else {
    // Code to execute if condition is false
}

Example
x := 3
if x > 5 {
    fmt.Println("x is greater than 5")
} else {
    fmt.Println("x is less than or equal to 5")
}

Here, the condition x > 5 is false, so the else block is executed, producing:
x is less than or equal to 5

If-Else If-Else Statement
Definition
The if-else if-else statement chain allows you to test multiple conditions in sequence. The first condition that evaluates to true will execute its corresponding block of code.
Syntax
if condition1 {
    // Code to execute if condition1 is true
} else if condition2 {
    // Code to execute if condition2 is true
} else {
    // Code to execute if none of the conditions are true
}

Example
x := 7
if x > 10 {
    fmt.Println("x is greater than 10")
} else if x > 5 {
    fmt.Println("x is greater than 5 but less than or equal to 10")
} else {
    fmt.Println("x is less than or equal to 5")
}

Since x is 7, the first condition is false, but the second condition is true, so the output is:
x is greater than 5 but less than or equal to 10

Switch Statement
Definition
The switch statement in Go is used to simplify complex if-else if chains by allowing a variable or expression to be tested against multiple cases. It's particularly useful for checking a variable against multiple possible values.
Syntax
switch expression {
case value1:
    // Code to execute if expression equals value1
case value2:
    // Code to execute if expression equals value2
default:
    // Code to execute if no cases match
}

Example
day := "Tuesday"
switch day {
case "Monday":
    fmt.Println("It's the start of the week.")
case "Tuesday":
    fmt.Println("It's Tuesday.")
case "Wednesday", "Thursday":
    fmt.Println("It's the middle of the week.")
default:
    fmt.Println("It's the weekend.")
}

Since day is "Tuesday", the output is:
It's Tuesday.

Switch Without an Expression
In Go, you can use a switch statement without an expression. This acts as a cleaner alternative to if-else chains and evaluates each case as a boolean expression.
x := 15
switch {
case x &#x3C; 10:
    fmt.Println("x is less than 10")
case x &#x3C; 20:
    fmt.Println("x is less than 20")
default:
    fmt.Println("x is 20 or more")
}

Here, the switch evaluates the first case that is true, producing:
x is less than 20

Practical Examples
Example 1: Simple Login Check
username := "admin"
password := "1234"

if username == "admin" &#x26;&#x26; password == "1234" {
    fmt.Println("Access granted.")
} else {
    fmt.Println("Access denied.")
}

This basic example checks if the username and password match the expected values and prints the appropriate message.
Example 2: Grade Evaluation Using Switch
grade := "B"
switch grade {
case "A":
    fmt.Println("Excellent")
case "B":
    fmt.Println("Good")
case "C":
    fmt.Println("Fair")
default:
    fmt.Println("Needs Improvement")
}

The switch statement evaluates the grade and prints the corresponding message.
Conclusion
Conditional statements in Go, including if, else, else if, and switch, provide powerful tools for controlling the flow of execution in your programs. These constructs allow you to handle different conditions effectively, making your code more flexible and easier to manage.

Explain the use of Go's conditional statements (if, switch, etc.) for controlling flow of execution?

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