Is the memory from primitive data types (int, char,etc) immediately released once they leave scope, or added to garbage collection for later release?

consider:

For x as integer=0 to 1000
dim y as integer
Next

If this doesn't add 1000 integers to the garbage collector for clean up later,
how does it treat string objects? would this create 1000 strings to clean up later?

For x as integer=0 to 1000
dim y as string=""
Next


How about structures that contain only int,string,etc... data types?

Classes that contain only managed resources?