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How to find the length of the pointer in Golang?
  • Last Updated : 05 Sep, 2019

Pointers in Go programming language or Golang is a variable which is used to store the memory address of another variable. Pointers in Golang are also termed as the special variables. The variables are used to store some data at a particular memory address in the system. The memory address is always found in hexadecimal format(starting with 0x like 0xFFAAF etc.).
In pointers, you are allowed to find the length of the pointer with the help of len() function. This function is a built-in function returns the total number of elements present in the pointer to an array, even if the specified pointer is nil. This function is defined under builtin.

Syntax:

func len(l Type) int

Here, the type of l is a pointer. Let us discuss this concept with the help of given examples:

Example:




// Go program to illustrate how to find the
// length of the pointer to an array
package main
  
import (
    "fmt"
)
  
// Main function
func main() {
  
    // Creating and initializing
    // pointer to array
    // Using var keyword
    var ptr1 [6]*int
    var ptr2 [3]*string
    var ptr3 [4]*float64
  
    // Finding the length of 
    // the pointer to array
    // Using len function
    fmt.Println("Length of ptr1: ", len(ptr1))
    fmt.Println("Length of ptr2: ", len(ptr2))
    fmt.Println("Length of ptr3: ", len(ptr3))
  
}

Output:

Length of ptr1:  6
Length of ptr2:  3
Length of ptr3:  4

Example 2:




// Go program to illustrate how to find
// the length of the pointer to an array
package main
  
import (
    "fmt"
)
  
// Main function
func main() {
  
    // Creating an array
    arr := [6]int{200, 300,
        400, 500, 600, 700}
      
    var x int
  
    // Creating pointer
    var p [4]*int
  
    // Assigning the address
    for x = 0; x < len(p); x++ {
      
        p[x] = &arr[x]
    }
  
    // Displaying result
    for x = 0; x < len(p); x++ {
      
        fmt.Printf("Value of p[%d] = %d\n", x, *p[x])
    }
  
    // Finding length
    // Using len() function
    fmt.Println("Length of arr: ", len(arr))
    fmt.Println("Length of p: ", len(p))
}

Output:

Value of p[0] = 200
Value of p[1] = 300
Value of p[2] = 400
Value of p[3] = 500
Length of arr:  6
Length of p:  4



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