Apa wae konstruksi aliran kontrol sing duwé Go?

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Aliran kontrol Go dirancang kanthi **minimal** — mung ana **siji keyword loop (`for`)**, ora ana parenthesis ing sekitering kondisi, lan braces sing wajib. Kesederhanaan iki sengaja, menehi siji cara sing jelas kanggo nindakake saben bab. ## Kenapa iki penting Aliran kontrol Go sing sengaja minimal nggambarake filosofi kesederhanaan lan duwe implikasi praktis sing perlu diweruhi. Karena mung duwe **`for`** (nutupi klasik, gaya while, tanpa wates, lan range loops) tegese ana siji konstruksi loop sing konsisten — `range` dadi cara idiomatik kanggo iterasi. Sintaks **ora parenthesis, braces wajib** lan forma **`if init; cond`** (khususé `if err := ...; err != nil`) nggambar idioma Go. `switch` **ora langsungan** minangka default ngilangi bug umum keluarga C, lan `switch` tanpa kondisi dadi alternatif if/else sing resik. Lan `defer` merupakan mekanisme pembersihan sing distingtif lan penting. Paham iki — lan apa bedane karo basa liya (siji loop, ora langsungan, defer) — dadi dhasar kanggo maca lan nulis Go idiomatik. ## if — ora parenthesis, karo statement init opsional ```go if x > 10 { // no parentheses around the condition; braces required fmt.Println("big") } else if x > 5 { fmt.Println("medium") } else { fmt.Println("small") } // if with an INIT statement — variable scoped to the if/else (very idiomatic) if err := doSomething(); err != nil { return err // `err` exists only within this if/else } ``` Forma `if init; condition` (ndeklarasi variabel sing scoped ing if) sangat umum ing Go — khususé pola cek kesalahan `if err := ...; err != nil`. ## for — SIJI-SATUNE loop, ing sawetara bentuk ```go // 1. classic three-part for for i := 0; i < 10; i++ { ... } // 2. while-style (just a condition) for x < 100 { x *= 2 } // 3. infinite loop for { ... break ... } // loop forever until break // 4. range — iterate slices, maps, strings, channels for index, value := range mySlice { ... } for key, value := range myMap { ... } for i, char := range "héllo" { ... } // i is byte index, char is a rune for range channel { ... } ``` Go **ora duwe `while` utawa `do-while`** — `for` nutupi kabeh kebutuhan looping. Bentuk `range` minangka cara idiomatik kanggo iterasi koleksi. ## switch — luwih resik tinimbang C (ora langsungan) ```go switch day { case "Sat", "Sun": // multiple values per case fmt.Println("weekend") case "Mon": fmt.Println("monday") // NO break needed — Go does NOT fall through by default! default: fmt.Println("weekday") } // switch with no condition = clean if/else chain switch { case score >= 90: grade = "A" case score >= 80: grade = "B" default: grade = "F" } ``` Bedane karo C/Java, `switch` Go **ora langsungan minangka default** (ora perlu `break`) — ngilangi bug klasik iku. Gunakake keyword `fallthrough` nalika anggone butuh. ## defer — jadwal pembersihan ```go func readFile() { f, _ := os.Open("file.txt") defer f.Close() // runs when the function RETURNS — guaranteed cleanup // ... use f ... } ``` `defer` jadwal panggilan kanggo ditindakake nalika fungsi sekitering bali — idiomatik kanggo pembersihan (nutup file, mbukak mutex).