Demonstrative Adjectives

Demonstrative Adjectives are this, that, these, those and are also known as demonstrative determiners, they modify a noun.

Example:
This car is good. I like those flowers.

As you see above they are placed before a noun.

Demonstrative Pronoun

This, that, these or those can be also used as a demonstrative pronoun, but in this case it stands on its own and replaces a noun.

Examples: This is bad. I like those.

Read more about Demonstrative Adjectives at Wikipedia