8.3. Accessing instance variables¶
You can read the values of an instance variable using the same syntax we used to write them:
int x = blank.x;
blank.x means “go to the object named
get the value of
x.” In this case we assign that value to a local
x. Notice that there is no conflict between the local
x and the instance variable named
x. The purpose
of dot notation is to identify which variable you are referring to
You can use dot notation as part of any C++ expression, so the following are legal.
cout << blank.x << ", " << blank.y << endl; double distance = sqrt(blank.x * blank.x + blank.y * blank.y);
In the active code below, we access the instance variables of
black using dot notation and output their values. Next, we output the
distance from the origin.