Should I use define or const?

const and #define both are used for handle constants in source code, but they few differences. #define is used to define some values with a name (string), this defined string is known as Macro definition in C, C++ while const is a keyword or used to make the value of an identifier (that is constant) constant.

Can we use const in PHP?

Until PHP 5.3, const could not be used in the global scope. You could only use this from within a class. This should be used when you want to set some kind of constant option or setting that pertains to that class.

What are the main differences between const vs define?

#define is a preprocessor directive. Things defined by #define are replaced by the preprocessor before compilation begins. const variables are actual variables like other normal variables.

Can we define array as constant in PHP?

Yes, You can define an array as constant. From PHP 5.6 onwards, it is possible to define a constant as a scalar expression, and it is also possible to define an array constant. It is possible to define constants as a resource, but it should be avoided, as it can cause unexpected results.

Why not use #define?

A #define (preprocessor macro) directly copies the literal value into each location in code, making every usage independent. This can hypothetically result in ambiguities, because the type may end up being resolved differently depending on how/where it’s used.

Is there const in Java?

Java doesn’t have built-in support for constants. A constant can make our program more easily read and understood by others. To define a variable as a constant, we just need to add the keyword “final” in front of the variable declaration.

What is difference between define and const in PHP?

The basic difference between these two is that const defines constants at compile time, whereas define() defines them at run time. const accepts a static scalar(number, string or other constants like true, false, null, __FILE__), whereas define() takes any expression.

Why use #define in C?

In the C Programming Language, the #define directive allows the definition of macros within your source code. These macro definitions allow constant values to be declared for use throughout your code. You generally use this syntax when creating constants that represent numbers, strings or expressions.

Why not use #define in C++?

Macros, like any #define are preprocessed, so the compiler does not see them at all. This means that there is never any symbols created for HELLO_MAC or THROW_EXCEPT , and so they cannot be seen in a debugger. They can also be confusing if you get compile errors, especially if they are long macros.

What’s the difference between a const and a constant in PHP?

One last point that should be made is that a const is always static and public. This means that you can access the const from within the class like so: From outside the class you would access it like this: Constant is just a constant, i.e. you can’t change its value after declaring.

Can a class constant be changed in PHP?

PHP – Class Constants Constants cannot be changed once it is declared. Class constants can be useful if you need to define some constant data within a class. A class constant is declared inside a class with the const keyword.

Why do you declare a property as static in PHP?

Declaring a class method or property as static makes them accessible without needing an instantiation of the class. A class constant is just like a normal constant, it cannot be changed at runtime. This is also the only reason you will ever use const for.

When do both classes have the same constant?

Both classes have same named constant CONST_INT. When child call method in parent class, there is different output between self and $this usage. [Editor’s note: that is already possible as of PHP 5.6.0.] Note, as of PHP7 it is possible to define class constants with an array.