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The define () function defines a constant.

Constants are similar to variables, except that:

• After setting, the constant value cannot be changed.
• The constant name does not need to start with the dollar sign ($)
• The scope does not affect constant access.
• A constant value can only be a string or number.

Syntax:

Define (name, value, case_insensitive)

Name: constant name;

Value: constant value;

Case_insensitive: default value:False, IndicatesCase Sensitive, True indicates not case sensitive;

 

Use the constant () function with the define () function:

Returns the constant value.

Explanation: this function is only applicable to Class constants.

 

Explanation:Scope refers to the availability range that limits a name.

Let's look for an example to practice:

Example:

<? Php <br/> define ("demo01", "Hello world! ", False); <br/> echo constant (" demo01 "); <br/>?>

Webpage output:

Warning: constant () [function. Constant]: Couldn't find constant demo01 in D: \ Wamp \ www \ com \ shyy \ newfile. php on line 3 <br/>

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