Apa bedane antara larik lan iris?

Question

Accepted Answer

**Larik** nduweni ukuran tetep sing dadi bagean saka jenise; **iris** minangka tampilan sing lentur lan dinamis menyang larik sing ndasar. Ing praktik, sampeyan meh tansah nggunakake **iris** — larik jarang ing Go sehari-hari.

## Larik — ukuran tetep

```go
var arr [5]int               // an array of exactly 5 ints (size is part of the type)
arr[0] = 10
fmt.Println(len(arr))        // 5 — size is fixed forever

// [3]int and [5]int are DIFFERENT types — can't assign one to the other
```

Ukuran larik tetep ing wektu kompilasi lan dadi bagean saka jenise (`[5]int` ≠ `[3]int`). Larik uga **tipe nilai** — nglirwakake utawa ngirim siji nggawe salinan larik kabeh. Rigiditas iki dadi alasan kenapa jarang digunakake langsung.

## Iris — dinamis lan lentur

```go
s := []int{1, 2, 3}          // a slice (no size in the brackets)
s = append(s, 4)             // grow it — append returns a new slice
fmt.Println(len(s), cap(s))  // length and capacity

nums := make([]int, 0, 10)   // make a slice: length 0, capacity 10 (pre-allocated)
```

Iris ora nduweni ukuran tetep — sampeyan nambah karo `append`. Iki minangka urutan dinamis sing kudu digunakake.

## Kepiye iris bisa gawé ing mburi layar

```text
A slice is a small struct: { pointer to underlying array, length, capacity }
  - len = number of elements currently in the slice
  - cap = size of the underlying array from the slice's start
append: if len < cap, reuses the array; if len == cap, allocates a BIGGER array & copies
```

## Iris nggawe tampilan (larik ndasar sing dienggo bareng — jebakan)

```go
original := []int{1, 2, 3, 4, 5}
sub := original[1:3]         // [2, 3] — a VIEW into the same backing array
sub[0] = 99                  // ⚠️ also changes original[1] → [1, 99, 3, 4, 5]!
```

Ngilas (`s[low:high]`) ora nggawe salinan — nggawe judhul iris anyar sing ngarahake menyang larik ndasar sing **padha**. Ngowahi siji bisa mpengaruhi liyane — sumber umum saka kutu halus. Gunakake `copy()` kanggo salinan sing mandiri.

## Kejutan realokasi append

```go
a := []int{1, 2, 3}
b := append(a, 4)            // may or may not share a's array depending on capacity
// safe pattern: always use the RETURNED slice from append
a = append(a, 4)
```

## Mengapa iki penting

Iris minangka salah sawijining fitur paling-digunakake lan paling-salah paham saka Go.

Ngerti yen larik minangka tipe nilai ukuran-tetep (jarang digunakake langsung) dene **iris** minangka tampilan sing lentur lan mirip referensi menyang larik ndasar (piranti sehari-hari) minangka fondasi.

Krucial, ngerti **perilaku larik ndasar sing dienggo bareng** — yen ngilasi nggawe tampilan, dudu salinan, supaya modifikasi bisa mpengaruhi iris liyane, lan yen `append` bisa utawa ora bisa realokasi — nyegah kelas gangguan aliasing sing halus lan angel didebug sing tangkep malah pangembang sing berpengalaman.

Nguasai iris (len vs cap, append, copy, jebakan ngenggo bareng) minangka kacaryan Go sehari-hari sing penting lan topik wawancara sing sering, amarga meh kabeh karya koleksi nggunakake dheweke.