Mashqlar

Bu bo’lim tuzilmalarni — struct, metod, interfeys, embedding va iotani — mustahkamlash uchun. Har bir masalani avval o’zingiz yeching, kodni ishga tushirib natijani tekshiring, keyin yechimga qarang.

1. Struct va uning maydonlari

Rectangle degan struct yasang: ichida Width va Height bo’lsin (ikkalasi ham int). Uni to’ldiring, Widthni boshqa qiymatga o’zgartiring va maydonlarni chop eting.

Yechimni ko’rish


package main
 
import "fmt"
 
type Rectangle struct {
    Width  int
    Height int
}
 
func main() {
    r := Rectangle{Width: 3, Height: 4}
    r.Width = 10 // maydonni o'zgartiramiz
    fmt.Println(r.Width, r.Height)
}

Natija:


10 4

2. Metod qo’shish

1-mashqdagi Rectanglega Area() int metodini qo’shing — u yuzani (Width * Height) qaytarsin. Value receiver ishlating.

Yechimni ko’rish


package main
 
import "fmt"
 
type Rectangle struct {
    Width  int
    Height int
}
 
func (r Rectangle) Area() int {
    return r.Width * r.Height
}
 
func main() {
    r := Rectangle{Width: 3, Height: 4}
    fmt.Println(r.Area())
}

Natija:

3. Pointer receiver bilan o’zgartirish

Counter structida Value int maydoni bo’lsin. Inc() metodini pointer receiver bilan yozing — u har safar chaqirilganda Valueni 1ga oshirsin. Uch marta chaqirib, natijani tekshiring.

Yechimni ko’rish


package main
 
import "fmt"
 
type Counter struct {
    Value int
}
 
func (c *Counter) Inc() { // pointer receiver - asl qiymat o'zgaradi
    c.Value++
}
 
func main() {
    c := Counter{}
    c.Inc()
    c.Inc()
    c.Inc()
    fmt.Println(c.Value)
}

Natija:

4. Interface va polimorfizm

Shape interfeysini yasang — unda faqat Area() float64 metodi bo’lsin. Circle (R float64) va Square (Side float64) turlarini shu interfeysga moslang. Ularni bitta []Shape ichiga solib, har birining yuzasini chop eting. Circle{2} uchun yuza math.Pi * 4, Square{3} uchun esa 9 chiqadi.

Yechimni ko’rish


package main
 
import (
    "fmt"
    "math"
)
 
type Shape interface {
    Area() float64
}
 
type Circle struct{ R float64 }
type Square struct{ Side float64 }
 
func (c Circle) Area() float64 { return math.Pi * c.R * c.R }
func (s Square) Area() float64 { return s.Side * s.Side }
 
func main() {
    shapes := []Shape{Circle{2}, Square{3}}
    for _, s := range shapes {
        fmt.Printf("%.2f\n", s.Area())
    }
}

Natija:


12.57
9.00

5. Embedding bilan qayta ishlatish

Animal structida Name string maydoni va Describe() string metodi bo’lsin (u "Men " + Name qaytarsin). Dog structiga Animalni embed qiling va Dogga Bark() string metodini qo’shing. Dog obyektidan ikkala metodni ham chaqiring.

Yechimni ko’rish


package main
 
import "fmt"
 
type Animal struct {
    Name string
}
 
func (a Animal) Describe() string {
    return "Men " + a.Name
}
 
type Dog struct {
    Animal // embedded - Describe() "ko'tariladi"
}
 
func (d Dog) Bark() string {
    return d.Name + ": vov!"
}
 
func main() {
    d := Dog{Animal{Name: "Rex"}}
    fmt.Println(d.Describe()) // Animal dan
    fmt.Println(d.Bark())     // Dog dan
}

Natija:


Men Rex
Rex: vov!

6. Type switch bilan turni aniqlash

describe(v any) funksiyasini yozing. U vning turiga qarab quyidagini chop etsin: int bo’lsa "butun son: <qiymat>", string bo’lsa "matn: <qiymat>", qolgan har qanday tur uchun "noma'lum tur". Type switch ishlating.

Yechimni ko’rish


package main
 
import "fmt"
 
func describe(v any) {
    switch x := v.(type) {
    case int:
        fmt.Printf("butun son: %d\n", x)
    case string:
        fmt.Printf("matn: %s\n", x)
    default:
        fmt.Println("noma'lum tur")
    }
}
 
func main() {
    describe(42)
    describe("salom")
    describe(3.14)
}

Natija:


butun son: 42
matn: salom
noma'lum tur

7. iota bilan enum va Stringer

Status degan enum turini yasang (int ustiga): Pending, Active, Closed — iota bilan 0, 1, 2 bo’lsin. Unga String() metodini qo’shing, shunda chop etilganda son o’rniga nomi ("Pending" va hokazo) chiqsin. Activeni chop etsangiz Active chiqishi kerak.

Yechimni ko’rish


package main
 
import "fmt"
 
type Status int
 
const (
    Pending Status = iota // 0
    Active                // 1
    Closed                // 2
)
 
func (s Status) String() string {
    switch s {
    case Pending:
        return "Pending"
    case Active:
        return "Active"
    case Closed:
        return "Closed"
    default:
        return "Unknown"
    }
}
 
func main() {
    s := Active
    fmt.Println(s)      // String() ishga tushadi
    fmt.Println(int(s)) // asl son
}

Natija:


Active
1

Bularni yechib bo’lsangiz, tuzilmalar asoslari mustahkam o’rnashgan deb bilavering. Keyingi xatoliklar bo’limida Go’da xatoliklar bilan qanday ishlanishini ko’ramiz.