Top 51 Go Programming Interview Questions
What is Go?
Answer
Go is a general-purpose language designed with systems programming in mind.It was initially developed at Google in the year 2007 by Robert Griesemer, Rob Pike, and Ken Thompson. It is strongly and statically typed, provides inbuilt support for garbage collection and supports concurrent programming. Programs are constructed using packages, for efficient management of dependencies. Go programming implementations use a traditional compile and link model to generate executable binaries.
What are the benefits of using Go programming?
Answer
Following are the benefits of using Go programming –
- Support for environment adopting patterns similar to dynamic languages. For example type inference (x: = 0 is a valid declaration of a variable x of type int).
- Compilation time is fast.
- InBuilt concurrency support: light-weight processes (via goroutines), channels, select statement.
- Conciseness, Simplicity, and Safety.
- Support for Interfaces and Type.
- Production of statically linked native embddingbinaries without external dependencies.
Does Go support type inheritance?
Answer
No support for type inheritance.
Does Go support operator overloading?
Answer
No support for method overloading.
Does Go support method overloading?
Answer
No support for method overloading.
Does Go support pointer arithmetics?
Answer
No support for pointer arithmetic.
Does Go Support generic programming?
Answer
No support for generic programming.
Is Go a case sensitive language?
Answer
Yes! Go is a case sensitive programming language.
What is the static type declaration of a variable?
Answer
Static type variable declaration provides assurance to the compiler that there is one variable existing with the given type and name so that compiler proceeds for further compilation without needing complete detail about the variable. A variable declaration has its meaning at the time of compilation only, the compiler needs actual variable declaration at the time of linking of the program.
What is the dynamic type of a variable in Go?
Answer
A dynamic type variable declaration requires the compiler to interpret the type of the variable based on the value passed to it. The compiler doesn’t need a variable to have type statically as a necessary requirement.
Can you declare multiple types of variables in single declaration in Go?
Answer
Yes, Variables of different types can be declared in one go using type inference.
var a, b, c = 3, 4, “foo”
How to print type of a variable in Go?
Answer
Following code prints the type of a variable –
var a, b, c = 3,4 “foo”
fmt.Printf(“a is Of type %T\n” ,a)
What is a pointer?
Answer
It’s a pointer variable which can hold the address of a variable.
For example –
var x = 5
var p *int
p =&x
fmt.Printf(‘’X = %d’’ , *p)
Here x can be accessed by *p.
What is the purpose of the break statement?
Answer
break terminates the for loop or switch statement and transfers execution to the statement immediately following the for loop or switch.
What is the purpose of continue statement?
Answer
continue causes the loop to skip the remainder of its body and immediately retest its condition prior to reiterating.
What is the purpose of the goto statement?
Answer
goto transfers control to the labelled statement.
Explain the syntax for ‘for’ loop.
Answer
The syntax of a for loop in Go programming language is-
For [condition | ( init; condition; increment ) | Range] {statement(s):}
Here is the flow of control in a for loop −
- if the condition is available, then for loop executes as long as the condition is true.
- if for a clause that is ( init; condition; increment ) is present then
The init step is executed first, and only once. This step allows you to declare and initialize any loop control variables. You are not required to put a statement here, as long as a semicolon appears.
Next, the condition is evaluated. If it is true, the body of the loop is executed. If it is false, the body of the loop does not execute and flow of control jumps to the next statement just after the for a loop.
After the body of the for loop executes, the flow of control jumps back up to the increment statement. This statement allows you to update any loop control variables. This statement can be left blank, as long as a semicolon appears after the condition.
The condition is now evaluated again. If it is true, the loop executes and the process repeats itself (body of the loop, then increment step, and then again condition). After the condition becomes false, the for loop terminates.
- if the range is available, then for loop executes for each item in the range.
Explain the syntax to create a function in Go.
Answer
The general form of a function definition in Go programming language is as follows –
func function_name( [prarmeter list ) [retuen_types] ( body of the function}
A function definition in the Go programming language consists of a function header and a function body. Here are all the parts of a function −
- func func starts the declaration of a function.
- Function Name− This is the actual name of the function. The function name and the parameter list together constitute the function signature.
- Parameters −A parameter is like a placeholder. When a function is invoked, you pass a value to the parameter. This value is referred to as the actual parameter or argument. The parameter list refers to the type, order, and the number of the parameters of a function. Parameters are optional; that is, a function may contain no parameters.
- Return Type− A function may return a list of values. The return_types is the list of data types of the values the function returns. Some functions perform the desired operations without returning a value. In this case, the return_type is not required.
- Function Body− The function body contains a collection of statements that define what the function does.
Can you explain multiple values from a function?
Answer
A Go function can return multiple values. For example _
Package main
Import ‘’fmt’’
Func swap(x , y sting) (string, string) {return y, x}
Func main () := swap (‘’Mahesh’’ , Kumar’’)
Fmt. Print1n(a, b)}
In how many ways you can pass the parameter to a method?
Answer
While calling a function, there are two ways that arguments can be passed to a function −
- Call by value− This method copies the actual value of an argument into the formal parameter of the function. In this case, changes made to the parameter inside the function have no effect on the argument.
- Call by reference −This method copies the address of an argument into the formal parameter. Inside the function, the address is used to access the actual argument used in the call. This means that changes made to the parameter affect the argument.
What is the default way of passing parameters to a function?
Answer
By default, Go uses call by value to pass arguments. In general, this means that code within a function cannot alter the arguments used to call the function and above-mentioned example while calling max() function used the same method.
What do you mean by function as the value in Go?
Answer
Go programming language provides flexibility to create functions on the fly and use them as values. We can set a variable with a function definition and use it as a parameter to a function.
What are the function closures?
Answer
Functions closure are anonymous functions and can be used in dynamic programming.
What are the methods in Go?
Answer
Go programming language supports special types of functions called methods. In method declaration syntax, a “receiver” is present to represent the container of the function. This receiver can be used to call the function using “.” operator.
What is the default value of a global variable in Go?
Answer
A global variable has default value as it corresponding 0 value.
What is the default of a pointer variable in Go?
Answer
The pointer is initialized to nil.
Explain the purpose of the function Printf().
Answer
Prints the formatted output.
What are lvalue and rvalue?
Answer
The expression appearing on the right side of the assignment operator is called an rvalue. Rvalue is assigned to an lvalue, which appears on the left side of the assignment operator. The lvalue should designate to a variable not a constant.
What is the difference between actual and parameters?
Answer
The parameters sent to the function at calling end are called as actual parameters while at the receiving of the function definition called as formal parameters.
Explain modular programming.
Answer
Dividing the program into subprograms (modules/function) to achieve the given task is the modular approach. More generic functions definition gives the ability to re-use the functions, such as built-in library functions.
What is a token?
Answer
A Go program consists of various tokens and a token is either a keyword, an identifier, a constant, a string literal, or a symbol.
Which keyword is used to perform unconditional branching?
Answer
Goto
What is an array?
Answer
The array is a collection of similar data items under a common name.
What is a nil Pointers in Go?
Answer
Go compiler assign a Nil value to a pointer variable in case you do not have exact address to be assigned. This is done at the time of variable declaration. A pointer that is assigned nil is called a nil pointer. The nil pointer is a constant with a value of zero defined in several standard libraries.
What is a pointer on pointer?
Answer
It’s a pointer variable which can hold the address of another pointer variable. It de-refers twice to point to the data held by the designated pointer variable. var an int
var ptr *int
var pptr**int
a= 3000
ptr = &a
pptr = &ptr
fmt.PrintF(Value available at **pptr = %d\n’’ ,**pptr)
Therefore ‘a’ can be accessed by **pptr.
What is structure in Go?
Answer
The structure is another user-defined data type available in Go programming, which allows you to combine data items of different kinds.
How to define a structure in Go?
Answer
To define a structure, you must use type and struct statements. The struct statement defines a new data type, with more than one member for your program. type statement binds a name with the type which is struct in our case.
The format of the struct statement is this
type struct_variable_type struct {
member definition;
member definition;
member definition
…
Member definition;
}
What is slice in Go?
Answer
Go Slice is an abstraction over Go Array. As Go Array allows you to define the type of variables that can hold several data items of the same kind but it does not provide any inbuilt method to increase the size of it dynamically or get a sub-array of its own. Slices cover this limitation. It provides many utility functions required on Array and is widely used in Go programming.
How to define a slice in Go?
Answer
To define a slice, you can declare it as an array without specifying size or use make function to create the one.
var a int
var ptr *int
var pptr**int
a= 3000
ptr = &a
pptr = &ptr
fmt.PrintF(Value available at **pptr = %d\n’’ ,**pptr)
var numbers []int /* a slice of unspecified size */
*/ number = = []int {0,0,0,0,0,0}*/
Numbers = make ([]int,5,5)/* a slice of length 5 capacity 5*/
How to get the count elements present in a slice?
Answer
To define a slice, you can declare it as an array without specifying size or use make the function to create the one.
How to get a sub-slice of a slice?
Answer
Slice allows lower-bound and upper bound to be specified to get the subslice of it using{lower-bound: upper]
What is range in Go?
Answer
The range keyword is used in for loop to iterate over items of an array, slice, channel or map. With array and slices, it returns the index of the item as an integer. With maps, it returns the key of the next key-value pair.
What are the maps in Go?
Answer
Go provides another important data type map which maps unique keys to values. A key is an object that you use to retrieve a value at a later date. Given a key and a value, you can store the value in a Map object. After the value is stored, you can retrieve it by using its key.
How to create a map in Go?
Answer
You must use make a function to create a map.
/* declare a variable, by default map will be nil*/
Var map_variable map[key_data_type]value_data_type
How to delete an entry from a map in Go?
Answer
delete() function is used to delete an entry from the map. It requires a map and corresponding key which is to be deleted.
What is type casting in Go?
Answer
Typecasting is a way to convert a variable from one data type to another data type. For example, if you want to store a long value into a simple integer then you can type cast long to int. You can convert values from one type to another using the cast operator as following –
Type_name(expression)
What re interfaces in Go?
Answer
Go programming provides another data type called interfaces which represents a set of method signatures. struct data type implements these interfaces to have method definitions for the method signature of the interfaces.
