Golang Control Structures If Switch For Complete Guide

GoLang Control Structures: if, switch, and for

GoLang, or Golang, is a statically typed, compiled programming language designed by Google. It provides straightforward and efficient control structures that include if, switch, and for for managing the flow of execution in a program.

1. if Statements

The if statement is used for decision-making in GoLang. It allows you to execute a block of code only if a specified condition is true.

Syntax:

if condition {
    // block of code to be executed if condition is true
}

With else:

if condition {
    // block of code to be executed if condition is true
} else {
    // block of code to be executed if condition is false
}

With else if:

if condition1 {
    // block of code to be executed if condition1 is true
} else if condition2 {
    // block of code to be executed if condition2 is true
} else {
    // block of code to be executed if both condition1 and condition2 are false
}

Important Points:

• Unlike other languages, GoLang doesn't require parentheses around the condition, but curly braces {} are necessary to define the block of code.
• The if statement can also include a short statement to execute before the condition is evaluated, which is helpful for scoping variables.

  if x := 5; x < 10 {
      fmt.Println("x is less than 10")
  }
  

2. switch Statements

The switch statement is used for multi-way branching. It replaces multiple if-else statements, making the code more organized and readable. Unlike some languages, GoLang's switch doesn't require a break statement after each case; it automatically exits the switch block at the end of a case.

Syntax:

switch expression {
case value1:
    // block of code to be executed if expression == value1
case value2:
    // block of code to be executed if expression == value2
default:
    // block of code to be executed if expression does not match any cases
}

Important Points:

• GoLang's switch evaluates each case in order and stops executing when a case succeeds, so there's no need for a break statement.
• The switch can be used without an expression (i.e., just switch), which can act like a clean and concise way to write long if-else-if chains.

  i := 2
  switch {
  case i%2 == 0:
      fmt.Println("Even")
  case i%2 != 0:
      fmt.Println("Odd")
  default:
      fmt.Println("Unknown")
  }
  

3. for Loops

The for loop is the only loop available in GoLang and is versatile enough to handle different situations that can be achieved with while and do-while loops in other languages.

Basic Syntax:

for initialization; condition; post {
    // block of code to be executed
}

Examples:

• Traditional for loop:

  for i := 0; i < 5; i++ {
      fmt.Println(i)
  }
  

• Without initialization and post:

  i := 0
  for ; i < 5; i++ {
      fmt.Println(i)
  }
  

• while loop equivalent:

  i := 0
  for i < 5 {
      fmt.Println(i)
      i++
  }
  

• Infinite loop:

  for {
      fmt.Println("This will run forever")
      break  // To avoid an infinite loop in actual code
  }
  

Important Points:

• The for loop in GoLang is more powerful and flexible than for, while, and do-while loops in other languages. The single for keyword covers all these functionalities.
• Unlike if and switch, parentheses around the conditional expressions are not used in for loops, but braces {} are used to define the block of code.
• The range keyword can be used with for loops to iterate over arrays, slices, maps, and channels, providing a simpler syntax compared to traditional for loops.