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;

The expression blank.x means “go to the object named blank and get the value of x.” In this case we assign that value to a local variable named x. Notice that there is no conflict between the local variable named x and the instance variable named x. The purpose of dot notation is to identify which variable you are referring to unambiguously.

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 Point object black using dot notation and output their values. Next, we output the distance from the origin.

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