You want to define an interface Shape with constants CIRCLE = 1, SQUARE = 2, and TRIANGLE = 3. Then, create a class Circle implementing Shape that returns the shape type constant. Which code snippet correctly implements this?
Ainterface Shape {
const CIRCLE = 1;
const SQUARE = 2;
const TRIANGLE = 3;
}
class Circle implements Shape {
public function getType() {
return Shape::CIRCLE;
}
}
Binterface Shape {
public const CIRCLE = 1;
public const SQUARE = 2;
public const TRIANGLE = 3;
}
class Circle implements Shape {
public function getType() {
return $this->CIRCLE;
}
}
Cinterface Shape {
const CIRCLE = 1;
const SQUARE = 2;
const TRIANGLE = 3;
}
class Circle implements Shape {
public function getType() {
return self::CIRCLE;
}
}
Dinterface Shape {
const CIRCLE = 1;
const SQUARE = 2;
const TRIANGLE = 3;
}
class Circle implements Shape {
public function getType() {
return Shape->CIRCLE;
}
}
Step-by-Step Solution
Solution:
Step 1: Define interface constants correctly
Constants in interface Shape are declared using const without visibility modifiers.
Step 2: Access constants correctly in implementing class
Inside Circle, access the constant using Shape::CIRCLE. Using $this->CIRCLE or self::CIRCLE is incorrect because constants belong to the interface, not the class instance or class itself.
Final Answer:
Option A code snippet correctly implements interface constants and access -> Option A
Quick Check:
Interface constants accessed as InterfaceName::CONSTANT [OK]
Quick Trick:Access interface constants with InterfaceName::CONSTANT, not $this or self [OK]
Common Mistakes:
Adding public before const in interface
Using $this->CONSTANT to access interface constant
Using self::CONSTANT inside class for interface constant
Using arrow operator (->) with interface name
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