We’ve defined our structs, but how do we create variables of that type? To use a struct we just defined, we have to create an instance of it. Assume we defined Point
from the last exercise. We could create an instance of it like so:
p1 := Point{x: 10, y: 12}
or
var p1 = Point{x: 10, y: 12}
Using this syntax, we can define values for each of the struct’s fields. However, Go allows us to rely on default values as well. We can omit fields:
p1 := Point{x: 10} // y will be set to 0
In fact, we can omit all fields to rely only on default values:
p1 := Point{} // x and y will be set to 0
The order of our struct definition allows us to avoid labeling our fields. The values are assigned from left to right according to how the fields are defined in the struct from top to bottom.
p1 := Point{10, 12} // Same as var p1 = Point{10, 12}
When not using labels, we must provide values for every field; otherwise, our code will not compile.
We’ve learned how to create struct instances, but how do we use them? In the next exercise, we will discover how to access and modify a struct’s values in our programs. For now, let’s practice creating some instances!
Instructions
A local school needs our help organizing its data.
Given the struct Student
, create an instance called peter
which represents the student named Peter Bookman who is 16 years old and is in grade 11.
Print peter
when finished.
Create a second instance of Student
called scott
which represents the student Scott Peterson who is in 12th grade (notice Scott’s age is not defined).
Print scott
when finished.