Go - Types & Keywords

Built-in Types

• Numbers: int, int64, float64, complex128
• Text: string, rune (Unicode code point), byte
• Aggregates: array, slice, map, struct
• Others: bool, pointer, interface

Zero Values and Inference

var s string // ""
var n int    // 0
var f float64 // 0
var b bool   // false
x := 10      // inferred int

Important Keywords

• defer, panic, recover
• go (start goroutine), select
• type, interface

Common errors

• Mixed types in expressions without explicit conversion (e.g., int + float64). Fix by converting: float64(i) + f.
• Using := at package level. Short declaration only works inside functions.

Practice

• Declare variables of types int, float64, and string, then print them with fmt.Printf using verbs %d, %f, and %q.
• Convert an int to float64 and add it to another float64 number.

Quick quiz

1. What’s the zero value of string?
2. When can you use :=?