the basics 2

Question 1

Conditionals

Answer 1

if x > 10 {
fmt.Println(“Large”)
} else if x > 5 {
fmt.Println(“Medium”)
} else {
fmt.Println(“Small”)
}

Question 2

Conditionals shorts

Answer 2

if val := compute(); val < 0 {
fmt.Println(“Negative”)
}

Question 3

Functions multiple

Answer 3

func divide(a, b float64) (float64, error) {
if b == 0 {
return 0, errors.New(“division by zero”)
}
return a / b, nil
}

Question 4

Functions named

Answer 4

func calc(a, b int) (sum int, diff int) {
sum = a + b
diff = a - b
return // implicitly returns sum, diff
}

Question 5

Exporting (Public):

Answer 5

Uppercase names are exported (e.g., Println, GetUser).
Importing:

go
import (
“fmt” // Standard library
“math/rand” // Subpackage
“github.com/user/pkg” // Third-party
)

Question 6

Package Declaration:

Answer 6

package main // Executable packages use main

Question 7

Type Casting Explicit

Answer 7

var i int = 42
var f float64 = float64(i) // int → float64

Question 8

Type Inference

Answer 8

x := 42 // int
y := 3.14 // float64
z := “hello” // string

Question 9

Arrays fixed

Answer 9

var arr [3]int // [0, 0, 0]
arr := [3]int{1, 2, 3} // Initialized

Key Point:
Size is part of the type ([3]int ≠ [4]int).

Question 10

Slices (Dynamic Arrays)

Answer 10

slice := []int{1, 2, 3} // No fixed size
slice = append(slice, 4) // [1, 2, 3, 4]
sub := slice[1:3] // [2, 3] (half-open)
Underlying Array:
Slices are references to arrays.

Question 11

Maps (Key-Value Pairs)

Answer 11

m := map[string]int{“a”: 1, “b”: 2}
m[“c”] = 3 // Insert
val, exists := m[“d”] // exists=false if missing

Key Rule:
Keys must be comparable (no slices/functions).

Question 12

make() (Pre-Allocation) Slices

Answer 12

slice := make([]int, 3, 5) // len=3, cap=5

Question 13

make() (Pre-Allocation) maps

Answer 13

m := make(map[string]int, 10) // Pre-allocates space
Use Case: Optimize performance by pre-sizing.

Question 14

Structs

Answer 14

Declaration:

type User struct {
Name string
Age int
}

Usage:

u := User{“Alice”, 30}
u.Age = 31 // Mutable

Question 15

Structs Embedded

Answer 15

type Admin struct {
User
Permissions []string
}