Go Pointers to Structs

The struct types store the variables of different data types and we use the struct variable to access the members of the struct.

In Go, we can also create a pointer variable of struct type.

Before you learn about pointers to struct, make sure to know about:

• Go Pointers
• Go Struct

Go Pointer to Struct

Suppose we have a struct like this

 type Person struct { name string age int }

Now, let's create a struct variable of Person type.

 person1 := Person{"John", 25}

Similar to this, we can also create a pointer variable of struct type.

 var ptr *Person

We can now assign the address of the struct variable to this pointer variable. Let's see an example.

 package main import "fmt" func main() { // declare a struct Person type Person struct { name string age int } // instance of the struct Person person1 := Person{"John", 25} 
 // create a struct type pointer that // stores the address of person1 var ptr *Person ptr = &person1
 // print struct instance fmt.Println(person1) // print the struct type pointer fmt.Println(ptr) }

Output

 {John 25} &{John 25}

In the above example, we have created a struct variable person1 that initialized the struct members; name to John and age to 25.

We have also created a pointer variable of the struct type that stores the address of person1.

 var ptr *Person ptr = &person1

Since the ptr now stores the address of person1, we get &{John 25} as the output while printing ptr.

 var ptr = &person1

Access struct using pointer in Golang

We can also access the individual member of a struct using the pointer. For example,

 // Program to access the field of a struct using pointer package main import "fmt" func main() { // declare a struct Person type Person struct { name string age int } person := Person{"John", 25} // create a struct type pointer that // stores the address of person var ptr *Person ptr = &person 
 // access the name member fmt.Println("Name:", ptr.name) // access the age member fmt.Println("Age:", ptr.age)
 }

Output

 Name: John Age: 25

In the above example, we have used the struct type pointer to access struct members:

• ptr.name - gives the value of the name member
• ptr.age - gives the value of the age member

Here, we have used the dot operator to access the struct members using the pointer.

 fmt.Println(ptr.name) // John fmt.Println((*ptr).name) // John

Change the Struct member in Go

Similarly, we can also use the pointer variable and the dot operator to change the value of a struct member. For example,

 // Program to change the struct member using pointer package main import "fmt" // create struct type Weather struct{ city string temperature int } func main() { // create struct variable weather := Weather{"California", 20} fmt.Println("Initial Weather:", weather) // create struct type pointer ptr := &weather 
 // change value of temperature to 25 ptr.temperature = 25 
 fmt.Println("Updated Weather:", weather) }

Output

 Initial Weather: {California 20} Updated Weather: {California 25}

In the above example, notice the line

 ptr.temperature = 25

Here, we have changed the value of the struct member temperature to 25 using the pointer variable ptr.