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bool and string

Learn boolean and text types.

bool and string

A bool can only be true or false; it is the result of comparisons. A string is text inside double quotes.

aktif := true
ad := "Ada"
yetiskin := 20 >= 18   // true
fmt.Println(aktif, ad, yetiskin)

Logical operators: && (and), || (or), ! (not).

String operations

Strings are joined with + and their byte length is taken with len. Backticks (`...`) write a raw string: \n inside isn't treated as an escape, and it can span several lines.

selam := "Merhaba " + "Go"
fmt.Println(selam, len(selam))  // Merhaba Go 10
yol := `C:\dosyalar\yeni`

Strings in Go are immutable; joining always produces a new string.

Practice Adult check

Declare ad := "Ada" and yas := 20. Compute yetiskin := yas >= 18 and print fmt.Println(ad + " yetişkin:", yetiskin).

Starter code

main.go
package main

import "fmt"

func main() {
    // buraya yaz
}

Sample solution

main.go
package main

import "fmt"

func main() {
    ad := "Ada"
    yas := 20
    yetiskin := yas >= 18
    fmt.Println(ad+" yetişkin:", yetiskin)
}

Expected output

Ada yetişkin: true

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 What is the result of <code>true &amp;&amp; !false</code>?

  • false
  • An error
  • 1
  • true Correct answer

Explanation: !false becomes true; true && true gives true.

2 The and operator

Question 
girisYapabilir := kayitli ____ sifreDogru
Answer 
girisYapabilir := kayitli && sifreDogru

Explanation: && requires both conditions to be true.

3 Expression and result

Term Meaning
5 > 3 true
!true false
"a" + "b" "ab"
len("Go") 2

All lessons in Beginner

1 Go basics

  1. What is Go?
  2. Installing Go
  3. Your first program
  4. go run and go build
  5. Comments and semicolons
  6. Summary - Go basics

2 Modules

  1. go mod init
  2. package and import
  3. The main package
  4. Multiple files
  5. go.sum and dependencies
  6. Summary - Modules

3 Variables

  1. Declaration with var
  2. Short declaration :=
  3. const and iota
  4. Zero value
  5. Type inference
  6. Summary - Variables

4 Data types

  1. int and float
  2. bool and string
  3. byte and rune
  4. Type conversion
  5. Type definitions
  6. Summary - Data types

5 Project: Calculator

  1. Project design
  2. Add and subtract
  3. Multiply and divide
  4. Command-line menu

6 Functions

  1. func declaration
  2. Parameters and return
  3. Multiple return
  4. Variadic functions
  5. Anonymous functions
  6. Summary - Functions

7 Control flow

  1. if, else if, else
  2. for loop
  3. Iterating with range
  4. switch and fallthrough
  5. break and continue
  6. Summary - Control flow

8 Array and slice

  1. Array declaration
  2. Slice declaration
  3. Appending with append
  4. Sub-slice
  5. len and cap
  6. Summary - Array and slice

9 Project: Shopping cart

  1. Product struct
  2. Adding to cart
  3. Computing total
  4. Printing the cart

10 Map

  1. Map declaration
  2. Adding elements
  3. Looking up in a map
  4. Deleting from a map
  5. Iterating a map with range
  6. Summary - Map

11 String

  1. String and byte
  2. String concatenation
  3. Conversion with strconv
  4. The strings package
  5. Rune and UTF-8
  6. Summary - String

12 Pointer

  1. What is a pointer?
  2. & and * operators
  3. The new function
  4. Pointers and functions
  5. Nil pointer
  6. Summary - Pointer

13 Struct

  1. Struct declaration
  2. Creating a struct
  3. Field access
  4. Struct embedding
  5. Struct and pointer
  6. Summary - Struct

14 Methods

  1. Method declaration
  2. Pointer receiver
  3. Value receiver
  4. Methods and embedding
  5. Method chaining
  6. Summary - Methods

15 Interface and error

  1. Interface declaration
  2. Implicit satisfaction
  3. The error interface
  4. Returning errors
  5. errors.Is and errors.As
  6. Summary - Interface and error

16 Beginner final

  1. Challenge 1 - Combined program
  2. Challenge 2 - Data structure
  3. Challenge 3 - Error handling
  4. Challenge 4 - Mini app