Intro

Question 1

First statement of any go program

Answer 1

package
e.g. package main

Question 2

Is package name a String?

Answer 2

No, package name is identifier

Question 3

Executable vs Library programs in Go

Answer 3

Executable: These are compiled into executable files, which can be executed in future.
Library: These are consumed/called inside the executable program

Question 4

Different characters included in “White space”

Answer 4

1. Tabs
2. Spaces
3. New Line

Question 5

How to consume code of other package inside our package?

Answer 5

Using “import” statement. The package name should always be inside the “double quote”.
e.g. import “fmt”

Question 6

Types of comments in Golang

Answer 6

Single line: //
Multi line : /* */

Question 7

Function declaration

Answer 7

1. Start with keyword “func”
2. Followed by function name
3. Followed by parenthesis
4. Followed by return type, nothing if void
5. Followed by body
   e.g.
   func main() {
   }

Question 8

How to read documentation of library programs?

Answer 8

Using following command:
go doc packageName // with or without double quote

Question 9

What is the full form of “fmt” package?

Answer 9

Formatted I/O

Question 10

What are the different boolean values supported by Go?

Answer 10

Only two - “true” and “false” (both small case)

Question 11

Is GO a statically typed language or Dynamically typed language ? What that means?

Answer 11

Go is a STATICALLY typed language, which simply means, it must know the “types” of all values before running the code.

Question 12

Which function and package is required to find the type of any value ?

Answer 12

Package: “reflect”
Function: “TypeOf”

Question 13

How to declare a variable in Go when we don’t know the value?

Answer 13

Use the keyword “var” followed by “name” of the variable followed by it’s “type”
»> var myVar int

Question 14

How to initialize a variable during declaration and after declaration ?

Answer 14

After declaration:
»> var myVar bool
»> myVar = true
During declaration
»> var myVar bool = true
OR
»> var myVar = true
During declaration we can omit the “TYPE” of the variable, as it will be automatically assigned by the value itself.

Question 15

What will be the value of the variables, if we don’t initialize it?

Answer 15

It will be the ZERO value of the TYPE. The “Zero” value will be different for different types. Following are the Zero values of different types:
int -> 0
rune -> ‘’
string -> ““
float -> 0
bool -> false

Question 16

What is the “short” variable declaration in Go-Lang?

Answer 16

“SHORT” variable declaration comes into the picture when we know the “value” of the variable during it’s declaration. In this we don’t need to mention the keyword “var” as well as “type” of the variable e.g.
»> var myVar int = 34 // long variable declaration
»> myVar := 34 // short variable declaration
The “semicolon” INDICATES the variable declaration. If we remove the “semicolon” it will become the “assignment”.

Question 17

Is it possible to just declare the variable without using it?

Answer 17

No, in Go, there will be an compilation error, if we don’t use any package, import or variable. Only “declaration” is not allowed, it must be used somewhere

Question 18

What are the Naming RULES in Go-Lang?

Answer 18

There are only two rules:
The first character of name of variable, function and Type must be started with a “letter”.
After first character, the other characters can be only “letters” and “numbers”
No special characters are allowed in the name
If the name of the variable/function/Type begins with “CAPITAL” letter, then it will be considered as “exported” and can be accessed outside the package (public)
If the name of the variable/function/Type begins with “SMALL” letter, then it will be considered as “private” and cannot not be accessed outside the package(private)

Question 19

Does Go supports “snake” case ?

Answer 19

No, we cannot use any special character in the name of variable/function/Type. Only Camel case is allowed.

Question 20

Can we perform math operation on multiple types ?

Answer 20

No, in Go, types must be same for any math operation. If Type is different then we need to do the “conversion”.

Question 21

How to convert int to float and vice-versa ?

Answer 21

Simply use the type, followed by parenthesis and then it’s value.
»> myInt := 12
»> myFloat := float32(myInt)