GoTheBiggerPicture

Question 1

Main problems solved by Go-Lang

Answer 1

1. In-efficient Compilation
2. In-efficient Execution
3. Complex programming model

Question 2

From Which language syntax is inspired in Go lang?

Answer 2

‘C Language’

Question 3

Is Go procedural or Object Oriented ?

Answer 3

It is both.

Question 4

Is Go Garbage collected ?

Answer 4

Yes Go language automatically performs garbage collection.

Question 5

what it means when we say Go is fully compiled language?

Answer 5

It means, the Go compiled code doesn’t requires a “mediator” runtime to execute the same. It can be directly executable by the OS.
Unlike other languages like Java or Python, which requires a “mediator” runtime to execute the compiled code, the Go doesn’t requires any runtime same.

Question 6

Does Go provides Single Binary output after compilation ?

Answer 6

yes, to make deployment easier, the Go compiler provides single binary output for deployment.

Question 7

When first version of Go was released and what’s its release cycle ?

Answer 7

First Version: 2012 - 1.0
Release Cycle: Every six Month
Current Version: 1.20

Question 8

What are the go inbuilt packages which provide network supports?

Answer 8

net and net/http

Question 9

Which package in Go language provides “concurrency” support ?

Answer 9

goRoutine

Question 10

How can we share resources between concurrent threads in Go ?

Answer 10

Using “channels”

Question 11

How Go lang generate OS specific binaries for Windows, OS X and Android?

Answer 11

Go uses following variables to create Platform specific binaries:
1. GOOS
2. GOARCH
Once we set these environment variables, Go automatically creates the OS specific binaries. e.g.
1. Windows: GOOS: windows & GOARCH: amd64
2. OSX: GOOS: darwin & GOARCH: amd64
3. Android: GOOS: android & GOARCH: arm

Question 12

Which package in GO is used to accept command line parameters ?

Answer 12

“Flag”

Question 13

What should be the first statement of any Go Source File ?

Answer 13

“package” statement.
It says where our source code sits in our Application.

Question 14

How to put a single line comment in Go ?

Answer 14

// This is a commented line

Question 15

How to put a multi-line comment in Go ?

Answer 15

/*
This is
multi line comment.
*/

Question 16

What is an Import statement ?

Answer 16

Import statement is used to import “external” package inside our package.

Question 17

What is an Import block ?

Answer 17

An import block allowed us to import multiple packages without repeating the word “import”. e.g.
import (
“os”
“fmt”
)

Question 18

What type of indentation is used by Go formatter to format the code - “Space” or “Tab”?

Answer 18

“Tab”.
It is a standard practice to use “Tab” for indentation, instead of “spaces”

Question 19

Do GO compiler throws error, if indentation is not provided by the user ?

Answer 19

No
Indentation should be used for code readability but it is not mandatory.

Question 20

Is it required to use semicolon at the end of each statement ?

Answer 20

No
Go compiler replaces the “new line” character with “semicolon”, so that it is not required by the user to put it at the end of each statement.

Question 21

What is wrong with following code ?
func main()
{
fmt.Println(“hello”)
}

Answer 21

The line “func main()” will be considered as a “statement”, hence Go compiler will put a Semicolon after this. Hence after compilation it will be look like this
func main();
{
fmt.Println(“hello”)
}
Hence we will get two errors for this:
1. function main without body
2. Semicolon is missing

Question 22

what is the sub command used for getting the “version” ?

Answer 22

go version
In above “go” is the command and “version” is the subcommand

Question 23

How to find out documentation about any “subcommand” in Go ?

Answer 23

“help” subcommand.
»> go help doc

Question 24

What is done by “run” subcommand ?

Answer 24

1. Compiles the code
2. Create a temporary “executable file” current directory
3. Executes the “temporary executable file”
4. clean the local workspace

Question 25

What is a Go Module ?

Answer 25

Go Module is a directory which contains the “go.mod” file. It can be seen as “workspace” or “project directory”.

Question 26

How to initialise a go module ?

Answer 26

go mod init <module></module>

Question 27

What is the standard format to name a Go Module ?

Answer 27

1. <repository-domain>/<user-name>/<repository-name>
   </repository-name></user-name></repository-domain>
2. All Lower Case
   e.g. githib.com/fil/my-repository

Question 28

What is the default content of go.mod file ?

Answer 28

1. Module Name
2. Go Version

Question 29

How to run an entire Module in Go ?

Answer 29

Use module identifier:
go run github.com/my-name/my-repository

Question 30

What is the keyword required to declare a variable ?

Answer 30

“var”

Question 31

What is the order of providing type in Variable declaration ?

Answer 31

The Type is always provided at the end of declaration in the format
var <variableName> <variableType> e.g.
var i int</variableType></variableName>

Question 32

How to declare and initialise variables in a “single line” with data type ?

Answer 32

var <variableName> <dataType> = <value>
e.g. var f float32 = 3.14</value></dataType></variableName>

Question 33

What is the shorthand way to declare and initialise variables without using the “var” keyword and data type

Answer 33

<variableName> := <variableValue>
e.g. firstName := "arthur"
</variableValue></variableName>

Question 34

How to do multi variable declaration and initialisation ?

Answer 34

This can be only done by using “Shorthand syntax”.
e.g. i, j = 12, 23
(Two names on left side and two values on right side)

Question 35

What’s a pointer variable ?

Answer 35

A variable which stores only “address” of another variable.

Question 36

How to declare a pointer variable ?

Answer 36

By Using “*” with variable type
e.g. var ptr *string

Question 37

What is the default value of pointer variable without initialisation ?

Answer 37

“nil”

Question 38

How to initialise an empty pointer variable ?

Answer 38

Using “new” function:
var ptr *string = new(string)

Question 39

What is “referencing” and “de-referencing” ?

Answer 39

Referencing: It means pointing to the address of variable
de-referencing: It means pointing to the “value” of the variable

Question 40

How to access the value of a variable, if we have it’s memory address (pointer) ?

Answer 40

By using Dereferencing variable.
e.g fmt.Println(*ptr)

Question 41

How to assign a value to the variable, if we have it’s memory address (pointer) ?

Answer 41

By using Deferencing variable:
e.g. *ptr = “myValue”

Question 42

How to save address of a variable into pointer variable ?

Answer 42

Using “address” variable:
e.g. ptr := &myvar

Question 43

What is a constant ?

Answer 43

A variable whose value cannot be changed

Question 44

How to declare a constant implicitly and explicitly ?

Answer 44

Implicit Declaration = Type determined as per the value of constant
e.g. const i = 23
Explicit Declaration = Type provided by the programmer
e.g. const i int = 23

Question 45

?What’s the advantage of implicit const declaration ?

Answer 45

In Implicit declaration, the compiler automatically changes the type of the varaible based on the operation:
e.g. const i = 2
i + 2 // int + int
i + 2.3 // int + float
In second operation, the compiler will automatically converts the constant into float type and then performs the operation

Question 46

What’s a constant block ?

Answer 46

A constant block is a package level block, where we can declare and intialize multiple constants without repeating the word “constant”
e.g const (
first = 23
second = 24
)

Question 47

what is iota keyword ?

Answer 47

It’s just a “int” constant sequencing keyword. It increments everytime we declare and use constants.