Summary - Data types
- Go course
- Beginner
- Lesson 24/90
- 4 min
Combine int, float, string and bool to write a profile card.
Data types summary
Basic types: int (integer), float64 (decimal), bool (true/false), string (UTF-8 text), byte (a byte) and rune (a character). Go doesn't convert types on its own; use explicit conversions like float64(n) and int(x), and strconv for text. With type you can define your own types and add methods to them.
var (
adet int = 3
fiyat float64 = 12.5
ad string = "Kalem"
stok bool = true
)Zero values
Every variable declared without a value has a zero value: 0 for numbers, false for bool, and "" for string. That's why Go has no "undefined" variables.
var n int
var s string
var b bool
fmt.Printf("%d %q %t\n", n, s, b) // 0 "" falsePractice Print the types
Declare adet := 3, fiyat := 12.5, ad := "Kalem", stok := true. Print the types of all four with fmt.Printf("%T %T %T %T\n", ...).
Starter code
package main
import "fmt"
func main() {
// buraya yaz
}Sample solution
package main
import "fmt"
func main() {
adet := 3
fiyat := 12.5
ad := "Kalem"
stok := true
fmt.Printf("%T %T %T %T\n", adet, fiyat, ad, stok)
}Expected output
int float64 string bool
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which format prints a variable's type?
- %v
- %d
- %s
- %T Correct answer
Explanation: fmt.Printf("%T", x) prints the variable's Go type (e.g. float64).
2 Print the type
fmt.Printf("____
", 3.5) // float64fmt.Printf("%T
", 3.5) // float64Explanation: %T prints the value's type.
3 Type and zero value
| Term | Meaning |
|---|---|
int |
0 |
float64 |
0 (0.0) |
bool |
false |
string |
"" |