Floyd's triangle in PL/SQL

Prerequisite - PL/SQL introduction In PL/SQL code groups of commands are arranged within a block. A block group related declarations or statements. In declare part, we declare variables and between begin and end part, we perform the operations. Floyd's triangle is a right-angled triangular array of natural numbers. It is defined by filling the rows of the triangle with consecutive numbers, starting with a 1 in the top left corner. Given a range of number and the task is to form Floyd's triangle. 

Examples:

Input: 1-29
Output:
 1
 2 3
 4 5 6
 7 8 9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28

Below is the required implementation: 

 
--floyd's triangle in PL/SQL 
DECLARE 
    --num, var_num variable declare 
    --num assign 1 
    num     NUMBER := 1; 
    var_num VARCHAR2(200); 
BEGIN 
    --loop  from 1 to 16 
    FOR i IN 1..16 LOOP 
        FOR j IN 1..i LOOP 
            var_num := var_num 
                       ||' ' 
                       ||num; 

            num := num + 1; 

            exit WHEN num = 16; 
        END LOOP; 

        --result print 
        dbms_output.Put_line(var_num); 

        exit WHEN num = 16; 

        var_num := NULL; 
    END LOOP; 
--end loop 
END; 
--end program 

Output:

 1
 2 3
 4 5 6
 7 8 9 10
 11 12 13 14 15