Lesson 3: Data Types¶

Big Picture¶

flowchart TD
    T["Go types"] --> N["Numeric"]
    T --> S["string"]
    T --> B["bool"]
    N --> I["integers<br/>int8 · int16 · int32 · int64<br/>uint8 · uint16 · uint32 · uint64"]
    N --> F["floats<br/>float32 · float64 (default)"]
    S --> R["made of bytes,<br/>runes (int32) = unicode code points"]
    I -.->|"Go requires EXPLICIT conversion"| C["float64(i)"]

Go has no implicit conversions — mixing int and float64 won't compile. Convert explicitly, always.

Concepts¶

Integer Types¶

Floating Point¶

• float32 — 32-bit precision
• float64 — 64-bit precision (default)

Strings¶

s := "Hello"           // Regular string
m := `Multi
line`                  // Raw string literal

Type Conversion¶

i := 42
f := float64(i)  // Explicit conversion required

Code Walkthrough¶

package main

import "fmt"

func main() {
    var i int = 42
    var f float64 = 3.14
    var b bool = true
    var s string = "hello"

    fmt.Println(i, f, b, s, len(s))
    fmt.Println(float64(i) * f) // explicit conversion
}

Check Your Understanding¶