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Without pointers, when a variable is passed into a function, only a copy of it is used inside the function. We can use pointers to modify values in our structs within a function. But how do we get a pointer to our struct?

Let’s explore this concept using the following struct as an example:

type Employee struct { firstName string lastName string age int title string }

We must first create an instance of Employee and then we create a pointer that will point to this instance. This is done like so:

func main() { steve := Employee{“Steve”, “Stevens”, 34, “Junior Manager”} pointerToSteve := &steve }

We can now use this pointer to change the values of the fields for steve. There are two ways to do this in Go:

(*pointerToSteve).firstName

Or a simpler, recommended method:

pointerToSteve.firstName

We can use these pointers to modify structs in our functions. Consider the following example:

func (rectangle *Rectangle) modify(newLength float32){ rectangle.length = newLength }

Notice that just inside the function modify() that rectangle is also a pointer. It is dereferenced without the use of the dereferencing operator just like pointerToSteve!

We now have the ability to change Struct values in our functions! Let’s get some practice in!

Instructions

1.

Write a function called updateBase() that will change the value of the base field of a Triangle instance.

After writing the function, call it within main. Set the new base to be 13.

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