Error: In stack of struct in go-lang get overwrite? How can we do deep-copy of struct in golang?

Question

I have created a stack of struct in Go.

type Stack struct {
    stack []Vehicle
}

I have this struct and method to create a new struct instance:-

type Vehicle struct {
Name string
Quantity map[string]interface{}
}

function NewVehicle(name string) *Vehicle {
v := &Vehicle{Name:name}
v.Quantity = make(map[string]interface{})
return v
}

What I am doing for example:-

m := NewVehicle("Two Wheeler")
m.Quantity['a'] = 10

// pushing stack 
Stack.push(clone(m))

m.Quantity['a'] = 20

Stack.pop(m)

Expected:-

As I pushed instance with Quantity['a'] = 10 when I pop the stack then it should give me value 10 of Quantity['a']

Actual:-

I am getting the value 20 of Quantity['a']

function clone(vehicle Vehicle*){}

Can anybody help in this, how deep copy of the struct before pushing in the stack? or what will be in the clone method to deep copy the struct?

Burak Serdar · Answer 1 · 2022-09-27T12:19:15.993

1

Map is a pointer to the actual map object, so if you need to deep-copy it, you have to do it manually:

func (v Vehicle) Copy() *Vehicle {
   ret:=NewVehicle(v.Name)
   for k,v:=range v.Quantity {
       ret[k]=v
   }
   return ret
}
...

stack.push(m.Copy())

edited Sep 27 '22 at 12:19

answered Sep 25 '22 at 16:54

Burak Serdar

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NewVehicle is return a pointer of struct then how will this work with that? – Deepak Sharma Sep 27 '22 at 07:10
NewVehicle is return pointer – Deepak Sharma Sep 28 '22 at 10:59

Error: In stack of struct in go-lang get overwrite? How can we do deep-copy of struct in golang?

1 Answers1