1
package main
2
import "fmt"
3
func main() {
4
    var numbers [5]int
5
    numbers[0] = 1
6
    numbers[1] = 2
7
    numbers[2] = 3
8
    numbers[3] = 4
9
    numbers[4] = 5
10

11
    fmt.Println("Numbers:", numbers)
12
}

1
package main
2
import "fmt"
3
func main() {
4
    numbers := []int{1, 2, 3, 4, 5}
5
    fmt.Println("Numbers:", numbers)
6
}

1
    numbers := []int{1, 2, 3}
2
    fmt.Println("Numbers:", numbers)
3
    // เพิ่มค่าเข้าไปใน slice
4
    numbers = append(numbers, 4, 5)
5
    fmt.Println("Updated Numbers:", numbers)

1
package main
2
import "fmt"
3
func main() {
4
    person := make(map[string]string)
5
    person["name"] = "Alice"
6
    person["city"] = "Bangkok"
7
    fmt.Println("Person:", person)
8
}

1
package main
2
import "fmt"
3
func main() {
4
    age := 30
5
    // สิ่งที่ golang ไม่เหมือนกับภาษาอื่นๆคือวงเล็บของ if ไม่ต้องมีวงเล็บครับ แต่จริงๆใส่ก็ได้นะเดี๋ยวมันก็ลบออกให้เอง
6
    if age >= 18 {
7
        fmt.Println("You are an adult.")
8
    } else {
9
        fmt.Println("You are a minor.")
10
    }
11
}

1
package main
2
import "fmt"
3
func main() {
4
    day := "Monday"
5
    switch day {
6
    case "Monday":
7
        fmt.Println("Start of the week.")
8
    case "Friday":
9
        fmt.Println("End of the week.")
10
    default:
11
        fmt.Println("Midweek.")
12
    }
13
}

1
package main
2
import "fmt"
3
func main() {
4
    // ลูปแบบ for ปกติ
5
    for i := 0; i < 5; i++ {
6
        fmt.Println("Iteration:", i)
7
    }
8

9
    // ลูปแบบ while
10
    count := 0
11
    for count < 5 {
12
        fmt.Println("Count:", count)
13
        count++
14
    }
15

16
    // ลูปแบบ for-each สำหรับ slice เราจะได้ใช้แบบนี้บ่อยๆ ครับ
17
    numbers := []int{1, 2, 3, 4, 5}
18
    for index, value := range numbers {
19
        fmt.Printf("Index: %d, Value: %d\n", index, value)
20
    }
21
}

1
package main
2
import "fmt"
3

4
// ฟังก์ชันที่ไม่คืนค่า
5
func greet(name string) {
6
    fmt.Printf("Hello, %s!\n", name)
7
}
8

9
// ฟังก์ชันที่รับพารามิเตอร์และคืนค่า
10
func add(a int, b int) int {
11
    return a + b
12
}
13

14
func main() {
15
    greet("Alice")
16
    result := add(5, 3)
17
    fmt.Println("Result:", result)
18
}

1
package main
2
import "fmt"
3
func divide(a int, b int) (int, error) {
4
    if b == 0 {
5
        return 0, fmt.Errorf("Cannot divide by zero")
6
    }
7
    return a / b, nil
8
}
9

10
func main() {
11
    result, err := divide(10, 2)
12
    if err != nil {
13
        fmt.Println("Error:", err)
14
    } else {
15
        fmt.Println("Result:", result)
16
    }
17
}

1
package main
2
import "fmt"
3

4
type Shape interface {
5
    Area() float64
6
}
7
type Circle struct {
8
    Radius float64
9
}
10

11
func (c Circle) Area() float64 {
12
    return 3.14 * c.Radius * c.Radius
13
}
14

15
func main() {
16
    var s Shape
17

18
    s = Circle{Radius: 5}
19
    fmt.Printf("Area of the circle: %.2f\n", s.Area())
20
}

1
package main
2
import "fmt"
3
type PaymentMethod interface {
4
    ProcessPayment(amount float64) error
5
}
6
type CreditCard struct {
7
    CardNumber string
8
}
9
func (cc CreditCard) ProcessPayment(amount float64) error {
10
    fmt.Printf("Processing credit card payment of $%.2f for card number %s\n", amount, cc.CardNumber)
11
    return nil
12
}
13
type PayPal struct {
14
    Email string
15
}
16
func (pp PayPal) ProcessPayment(amount float64) error {
17
    fmt.Printf("Processing PayPal payment of $%.2f for email %s\n", amount, pp.Email)
18
    return nil
19
}
20
type Bitcoin struct {
21
    WalletAddress string
22
}
23
func (bc Bitcoin) ProcessPayment(amount float64) error {
24
    fmt.Printf("Processing Bitcoin payment of $%.2f for wallet address %s\n", amount, bc.WalletAddress)
25
    return nil
26
}
27

28
func main() {
29
    var payment PaymentMethod
30
    // ทีนี้ user จะจ่ายด้วยอะไรผมไม่รู้แหละ แต่ผมแค่รู้ว่ามันต้อง implement interface PaymentMethod เท่านั้นเองครับ
31
    payment = CreditCard{CardNumber: "1234-5678-9012-3456"}
32
    payment.ProcessPayment(100.00)
33
    payment = PayPal{Email: "alice@example.com"}
34
    payment.ProcessPayment(50.00)
35
    payment = Bitcoin{WalletAddress: "1A1zP1eP5QADt9KZz5rYvG8M2sT1gZ"}
36
    payment.ProcessPayment(0.005)
37
}

1
package calculator
2
func Add(a int, b int) int {
3
    return a + b
4
}
5
func Subtract(a int, b int) int {
6
    return a - b
7
}

1
package main
2
import (
3
    "fmt"
4
    "golang-intro/calculator"
5
)
6
func main() {
7
    sum := calculator.Add(5, 3)
8
    difference := calculator.Subtract(5, 3)
9
    fmt.Println("Sum:", sum)
10
    fmt.Println("Difference:", difference)
11
}

1
package main
2
import "fmt"
3
type User struct {
4
    Name string
5
    Age  int
6
}
7
func updateUser(user *User) {
8
    user.Age++
9
}
10
func main() {
11
    user := User{Name: "Alice", Age: 30}
12
    fmt.Printf("Before update: %+v\n", user)
13
    updateUser(&user)
14
    fmt.Printf("After update: %+v\n", user)
15
}