This Is Where Anybody can Learn Go Basics! Lets Do it One By One !
usego run hello_world.gocommand to run a golang program.
We have to declare packages that has to be executed alongside. Every Packages has a Path and A Name Assiciated with.Packages are declared on top of the code.
There are many operators in go like in anyother language.
> Arithmetic Operators
> Assignment Operators
> Comparison Operators
> Logical Operators
> Bitwise Operators
- Other Operators * Concatenation using + or += operators, & for address of, * for pointer to, <- for Receive operator.
Special string comrise a backlash () followed by a letter or combination of digits for controlling output on monitor. For instance : newline(\n), carriage returns(\r),tabs,(\t) and non printing characters in Screen.
> \\ for \ character
> \' for ' character
> \' for ' character
> \? for ? character
> \a alert or bell
> \b for backspace
> \f for form feed
> \n for new line
> \r for carriage return
> \t for horizontal tab
> \v for vertical tab
> \o octal number of one to three digits
> \xhh... hexadecimal number of one or more digits
> if statements
> if else statements
> Nested if statements
> Switch statements
> Select statements
Follow a program in code section for more in details.
Loop is a programming structure that repeats a sequence of instructions until a specific condition is met. Go employs for loops and nested for loops for this purpose.
for initialization; condition; increment {
// loop body
}
Controlling loops are empoyed using
> break
> continue
> goto statements
Type conversion 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. Its syntax is as follows −
type_name(expression)
syntax:
func function_name( [parameter list] ) [return_types]
{
body of the function
}
A function definition in Go programming language consists of a function header and a function body. Here are all the parts of a function −
Func − It starts the declaration of a function.
Function Name − It 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 actual parameter or argument. The parameter list refers to the type, order, and 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 the not required.
Function Body − It contains a collection of statements that define what the function does.
The function that called with the varying number of arguments is known as variadic function. Or in other words, a user is allowed to pass zero or more arguments in the variadic function. fmt.Printf is the example of the variadic function, it required one fixed argument at the starting after that it can accept any number of arguments. e.g variadic.go
Recursion is the process of repeating items in a self-similar way. The same concept applies in programming languages as well. If a program allows to call a function inside the same function, then it is called a recursive function call.
recursion.go
Go supports anonymous functions, which can form closures. Anonymous functions are useful when you want to define a function inline without having to name it. e.g closure.go
Every variable is a memory location and every memory location has its address defined which can be accessed using ampersand (&) operator, which denotes an address in memory.A pointer is a variable whose value is the address of another variable, i.e., direct address of the memory location. Like any variable or constant, you must declare a pointer before you can use it to store any variable address.
syntax :
`var var_name *var-type`
var ip *int /* pointer to an integer */
var fp *float32 /* pointer to a float */
e.g : pointers.go
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.
e.g. : nil_pointer.go
On most of the operating systems, programs are not permitted to access memory at address 0 because that memory is reserved by the operating system. However, the memory address 0 has special significance; it signals that the pointer is not intended to point to an accessible memory location. But by convention, if a pointer contains the nil (zero) value, it is assumed to point to nothing.
To check for a nil pointer
if(ptr != nil) /* succeeds if p is not nil */
if(ptr == nil) /* succeeds if p is null */
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Go arrays allow you to define variables that can hold several data items of the same kind. Structure is another user-defined data type available in Go programming, which allows you to combine data items of different kinds.
Structures are used to represent a record
syntax :
definition :
type struct_variable_type struct {
member definition;
member definition;
...
member definition;
}
declaration of stucture variables :
variable_name := structure_variable_type {value1, value2...valuen}
e.g. : structures.go
You can pass a structure as a function argument in very similar way as you pass any other variable or pointer. e.g. : structures_as_function_arguments.go
You can define pointers to structures in the same way as you define pointer to any other variable
var struct_pointer *Books
Now, you can store the address of a structure variable in the above defined pointer variable. To find the address of a structure variable, place the & operator before the structure's name
struct_pointer = &Book1;
To access the members of a structure using a pointer to that structure, you must use the "." operator
struct_pointer.title;
e.g. : pointers_to_structures.go
Go does not have classes. However, you can define methods on types.A method is a function with a special receiver argument.The receiver appears in its own argument list between the func keyword and the method name.
Go programming provides another data type called interfaces which represents a set of method signatures. The struct data type implements these interfaces to have method definitions for the method signature of the interfaces.
Go programming language provides a data structure called the array, which can store a fixed-size sequential collection of elements of the same type. An array is used to store a collection of data, but it is often more useful to think of an array as a collection of variables of the same type. Instead of declaring individual variables, such as number0, number1, ..., and number99, you declare one array variable such as numbers and use numbers[0], numbers[1], and ..., numbers[99] to represent individual variables. A specific element in an array is accessed by an index. All arrays consist of contiguous memory locations. The lowest address corresponds to the first element and the highest address to the last element.
syntax :
declaration :var variable_name [SIZE] variable_type
initialization : var balance = [5]float32{1000.0, 2.0, 3.4, 7.0, 50.0}
accesing array elements : float32 salary = balance[9]
e.g. : array.go
Go programming language allows multidimensional arrays.
syntax :
Delcaration :
var variable_name [SIZE1][SIZE2]...[SIZEN] variable_type
Initialisation :
var threedim [5][10][4]int
for 2 dimensional array e.g. : array_2_dimensional.go