Introduction to Basic Syntax in Go Programming

1. Hello World

The first program you usually write when learning a new programming language is the "Hello World" program. In Go, it looks like this:

package main

import "fmt"

func main() {
    fmt.Println("Hello, World!")
}
                

Explanation:

• The package main line tells Go that this is the main package for the program.
• The import "fmt" line imports the "fmt" package, which contains functions for formatted I/O operations.
• The func main() line defines the main function, which is the entry point for a Go program.
• fmt.Println("Hello, World!") prints "Hello, World!" to the console.

2. Variables

Variables in Go can be declared using the var keyword or the shorthand := syntax.

package main

import "fmt"

func main() {
    var name string = "John"
    age := 30
    fmt.Println("Name:", name)
    fmt.Println("Age:", age)
}
                

Explanation:

• var name string = "John" declares a variable named name of type string and initializes it with the value "John".
• age := 30 declares a variable named age and initializes it with the value 30. The type of age is inferred as int.

3. Basic Data Types

Go has several basic data types:

• int - integer
• float64 - floating-point number
• string - sequence of characters
• bool - boolean (true or false)

package main

import "fmt"

func main() {
    var a int = 10
    var b float64 = 3.14
    var c string = "Hello"
    var d bool = true

    fmt.Println("Integer:", a)
    fmt.Println("Float:", b)
    fmt.Println("String:", c)
    fmt.Println("Boolean:", d)
}
                

4. Constants

Constants are declared using the const keyword and cannot be changed after their declaration.

package main

import "fmt"

func main() {
    const pi = 3.14159
    const greeting = "Hello, Go!"
    
    fmt.Println("Pi:", pi)
    fmt.Println("Greeting:", greeting)
}
                

5. Conditional Statements

Conditional statements in Go are similar to other programming languages. The if statement is used to execute code based on a condition.

package main

import "fmt"

func main() {
    age := 20

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

6. Loops

Go supports for loops, which are used to iterate over a range of values or until a condition is met.

package main

import "fmt"

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

    // Using a while-like loop
    j := 0
    for j < 5 {
        fmt.Println("j =", j)
        j++
    }
}
                

7. Functions

Functions in Go are defined using the func keyword. They can take parameters and return values.

package main

import "fmt"

func add(a int, b int) int {
    return a + b
}

func main() {
    result := add(3, 4)
    fmt.Println("Result:", result)
}
                

Explanation:

• func add(a int, b int) int defines a function named add that takes two parameters of type int and returns an int.
• The return a + b statement returns the sum of a and b.

8. Arrays and Slices

Arrays in Go have a fixed size, while slices are dynamically-sized, more flexible views into the elements of an array.

package main

import "fmt"

func main() {
    var arr [3]int = [3]int{1, 2, 3}
    fmt.Println("Array:", arr)

    slice := []int{4, 5, 6}
    fmt.Println("Slice:", slice)
}
                

9. Maps

Maps in Go are used to store key-value pairs.

package main

import "fmt"

func main() {
    capitals := map[string]string{
        "France": "Paris",
        "Japan": "Tokyo",
    }

    fmt.Println("Capital of France:", capitals["France"])
    fmt.Println("Capital of Japan:", capitals["Japan"])
}
                

10. Conclusion

This tutorial introduced the basic syntax of Go programming, covering topics such as variables, data types, constants, conditional statements, loops, functions, arrays, slices, and maps. With these fundamentals, you can start exploring more complex features and libraries in Go.