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GO Interview Questions

Go is a new programming language that is used for system programming developed at Google. Go is an open-source programming language that is also called Golang

Go programming language is designed for the system programming which is developed at Google.

Go is designed as an open-source programming language so it's all free and it will have a lot of functions. other qualities of Golang are

  • Simple
  • Reliable
  • Easy to build and compile
  • Highly efficient

Go programming language is created by

  • Robert Griesemer
  • Rob Pike
  • Ken Thompson

Golang is developed in 2009 at Google.

Programs in Golang are created using many packages. Every program in GO starts with the main package and it can import the packages using path "fmt" and "math/rand".

Generic programming means writing a code that will work with many data types like arrays. Incase of the GO programing language, it doesn't support Generic programming.

Yes, the Go programming language is case-sensitive. We have to be careful while using uppercase and lowercase alphabets.

String literal is a string constant that is formed by combining two or more characters. In Golang there are two types of strings

  1. 1. Raw string literals: Raw strings are the combination of characters between back quotes. Raw string doesn't have any escape characters in it.
  2. 2. Interpreted String Literals: these are the string literals in Golang that are written in double quotes. it contains escape characters but does not have any newlines.

Workspace is an environment where we can write Go program code. it has the GO code. The workspace is composed of three directories as its root. They are

  • "src"
  • "pkg"
  • "bin"

In the GO programming language, A workspace is composed of three directories at its root. among that directories, the "src" directory contains the source code which is arranged as packages.

Go programming workspace consists of three directories, among them, the "pkg" GO directory contains the package objects.

In GO programming workspace, the "bin" directory contains all the executable commands that can be used in GO programming.

In GO programming, the boolean type has the default value false.

GOPATH is an environment variable in GO programming which able to specify the location of a GO workspace. Before starting the programming in GO, we have to set this GOPATH environment variable.

GO programming is one of the latest programming languages that is developed at Google. it has many features or advantages they are

  1. Very fast and quick compile time
  2. Supports high language level concurrency
  3. Has an efficient garbage collection
  4. Wise use of resources efficiently
  5. Supports many safety features
  6. Functions treat as first-class objects in GO programming

Some of the built-in supports of GO programming language are

  • Container: heap/list/container
  • Webserver: http/net
  • Cryptography: md5/crypto/sha1
  • Compression: gzip
  • Database: sql

The GO programming language does not support the type inheritance.

Operator overloading is a kind of polymorphism in which the same operator can be used in different operations in an object-oriented language.  

GO programming language has No support for the Operator overloading

Method overloading is a concept where the programming language allows the class to define different methods but with the same name.

GO programming language doesn't support the method overloading.

Pointer arithmetics are also called address arithmetics which means we can do arithmetic operations like addition and subtraction from a pointer address. It depends on the size of the datatype that the pointer points to.

GO programming language doesn't have support for the pointer arithmetics.

Yes, the GO programming language is case-sensitive. 

The static variable declaration means we are declaring a variable statically whose value and datatype don't change inside the GO program.

Declaring a variable statically means we are telling the compiler that the variable name and type don't change. so that the compiler can compile the code without further checking the variable. this variable declaration is done in compiling time.

 

In the dynamic declaration of a variable in GO programming, the variable type and name is declared dynamically,

In this declaration, the compiler has to check the type of the variable after the value is passed into the variable,

Yes, it is possible to declare different variable types in a single line of code in GO programming using type inference, for example

var a, b, c = 1, 2, "go"

For printing the variable type in GO programming using the printf,  see the below code

var a, b, c = 3, 4, "go"  
fmt.Printf("a is of type %T\n", a)

 

A Pointer is a variable that holds the address of another variable instead of a specific value. for example

var y = 10
var p *int
p = &y
fmt.Printf("y = %d", *p)

Break statement is used to break the execution of a for loop or a switch case and transfer the control of program execution the next line just after the for loop or switch case in GO programming.

A continue statement inside a loop will continue the execution of the loop by skipping the part of the loop body below the continue statement. It reset the condition of the loop too.

GOTO is used to change the user control or alter the flow of the program to some other part of the program. It transfers the control from one point to a labeled statement.

As we know if-else is a conditional statement that helps to execute the code in the if part when it satisfies the condition. else it executes the else part. 

syntax of if-else

if  condition 
   { 
          code to be executed 
   }
else 
  {
         code to be executed 
  }

For is used for looping a set of code until the condition is false. It helps to print a sequence and much more. 

Syntax of FOR loop is

for [condition |  ( initialization; condition; increment ) | Range] \
{
   code;
}

Go programming language supports functions and the syntax for creating a function in the GO programming language is as follows

func function_name( [parameter list] ) [return_types]  
{  
   body of the function  
}   

Go programming supports the short declaration, but the short declaration can only be done inside a function in the Go programming language.

Yes, We can return multiple values from a function in the Go programming language.

In GO programming the arguments or parameters can be passed into a function using two different methods that include.

  • Call by value: In this method, the actual value is passed to the function into the formal parameter
  • Call by reference: In this method, the address of the value to be passed is copied into the formal parameters.

In GO programming, the default method for passing a value or a parameter into a function is copying the actual value of the parameter into the formal parameters. that is Call by value method

GOlang allows the program or user to create a function while the programming is running without interrupting the run of the program and use them as values.

In this method, we can set a variable while defining the function and use them as arguments in the function.

Go programming language supports a special feature called Anonymous functions called Function closures, which can be used in dynamic programming.

Closure functions reference a variable that is declared outside the function itself.

Methods are a special type of function in Go programming which is similar to the other GO functions but has a receiver argument in it, which represents the container of the function. With the help of the receiver argument, we can all the function using '.' operator.

Each variable in GOlang has a specific type. the default value of a local variable in the GO programming language is zero.

Default value of a global variable in GO programming language is 0

The default value of a pointer variable in the Go programming language is Zero. Every pointer variable is initialized to zero in GOlang.

Printf() statement in GO programming language is used to display the output which is formatted output.

lvalue in GO programming language is the value that is on the left side of an assignment operator. lvalue must not be a constant.

rvalue is the value that is on the right side of the assignment operator. 

The actual parameter is the real value that we need to send from the calling function or the main program.

The formal parameter in the Go programming language is the variable that receives the actual parameters inside the function.

Declaration of a variable means we are assigning a type to the variable such as integer, char, float, etc. 

Defining a variable means we are adding or assigning a value to that variable.

Modular programming is like object-oriented programming which means we are dividing the program into different sub-programs like functions that can be called for doing a task.

Modular program functions can be called many times so it add reusability to the function.

In the GO program we have to use keywords, string literals, constants, identifiers, or a symbol which can be collectively called a token in Golang.

In GO programming we have the GOTO statement for unconditional branching.

An array is a collection of elements of the same datatype which can be accessed using an index variable by incrementing the variable.

A pointer is indicated by a ' * ' along with the type of the value that the pointer points to in the Go programming language.

In GO programming, we have to run the below line of code to get the string formatted. 

return fmt.Sprintf ("at %v, %s" , e.When , e.What )

 

In GO programming we have a special method which means we have a special type of switch that is dedicated to checking the type of a variable during the program run time.

Panic is a built-in function in go programming which is used for error handling.

Go programming language supports a large number of datatypes which is broadly divided into four types

  • Basic type: Integers, characters, booleans, etc
  • Aggregate type: Array and structures
  • Reference type: pointers, slices, maps, functions, channels
  • Interface type

A pointer that is assigned the value nil or zero is called nil pointers. GO compiler can assign a pointer to nill value if it is not correctly assigned to an address.

The pointer on pointer is a pointer that holds the address of another pointer variable in Go programming. it is denoted by ' ** '

The structure is an aggregate type data type in GO programming language that can able to hold the collection of data of different data types.

Structure in Go programming is defined using the keyword "struct" Struct contains different type members inside it which have open and close braces.

Syntax

type struct_variable_type struct {
   member def;
   member def;
   ...
   member def;
}

Slice in GO programming is a data structure very similar to Arrays. Slice is much more efficient and flexible compared to arrays.

It can also store elements of the same data type just like the arrays and can be indexed using a variable.

The difference is the length of a Slice is not fixed like arays. It means the size of a slice can be changed inside the program.

Every slice index starts at the element zero and the last element will be on the position slice size - 1.

We have two methods for creating a slice.

  1. First, we can use the function "make" to create a Slice in GO programming

    var elements []int 
    /* elements == []int{0,0,0,0,0}*/

  2. The second is to define a slice just like array definition but not mention the size.

    elements = make([]int,7,7) /* creates a slice of length 7 and capacity 7*/

 

For counting the elements in a slice We have the function len() in GO programming which returns the number of elements in a slice.

cap() function in GO programming can be applied on a slice to get the capacity of the slice. It means it can return how many elements a slice can store.

For selecting a specific part of a slice that we can call a sub slice by using the upper and lower bound in GO programming

The range is a keyword in GO programming which is used in the for loop to iterate through the elements in an array, slice, channel, or map. 

The map is an important datatype in GO programming which helps to store a value with a corresponding key.

So using the key we can retrieve the value that is stored in response to the key.

Key-value must be unique like the primary key in the database.

The syntax for creating a map in GO programming is as below

var map_variable map[key_data_type]value_data_type

For removing an element from a map in GO programming we have to use the function delete(), using the key of the value that we need to delete.

Typecasting is the method by which we can convert a variable from one type to another using the cast operator. GO programming language supports typecasting.

the interface is a GOlang data type that helps to represent a set of methods.

Goroutine is a special function in GO programming that runs parallel with other goroutine functions or methods in the Go language. In Go programs, it uses many goroutines running parallel. 

 

To create a goroutine in Go programming, we have to use the keyword 'go' before the function.

go f(a,b,c)

We have to use the ' + ' operator in GO programming which do the concatenation of two strings.

Use the below code to display the combinations of a slice of a string in GO programming

package main
import "fmt"


func Perm(a []rune, f func([]rune)) {
        perm(a, f, 0)
}

func perm(a []rune, f func([]rune), i int) {
        if i > len(a) {
                f(a)
                return
        }
        perm(a, f, i+1)
        for j := i + 1; j < len(a); j++ {
                a[i], a[j] = a[j], a[i]
                perm(a, f, i+1)
                a[i], a[j] = a[j], a[i]
        }
}

func main() {
Perm([]rune("abc"), func(a []rune) {
        fmt.Println(string(a))
})
}

We know about a goroutine in GO programming, Channel is a path through which a goroutine communicates with the other goroutines. In normal cases, these goroutines can send and receive data at the same time.

Yes, the Go programming language is a multithreaded programing language that not only supports multithreading but its basic design is based on multithreading.

In the Go programming language, the command line arguments can be accessed by the os.Args variables. 

A variable is said to be shadowing another variable in GO programming language if that variable overrides the scope of a variable inside some function.

Suppose a variable in go programming is declared inside a function with the same name and type as a variable that is declared outside the function.

GO programming language is very fast in computation because of the following reasons,

  1. Small and simple syntax
  2. More concurrency
  3. Fast compile system
  4. Very less dependency on servers
  5. All hyperlinks and libraries combine into a binary file.

Yes, the GO process will take a large amount of memory because in GO programming the memory allocator takes and keeps some amount of virtual memory in advance for allocation.

Maps in Go programming is considered as reference types.