Switching back to PL/SQL for Problem 17 of Project Euler.

## Problem 17:

### Number Letter Counts

If the numbers 1 to 5 are written out in words: one, two, three, four, five, then there are 3 + 3 + 5 + 4 + 4 = 19 letters used in total.

If all the numbers from 1 to 1000 (one thousand) inclusive were written out in words, how many letters would be used?

NOTE: Do not count spaces or hyphens. For example, 342 (three hundred and forty-two) contains 23 letters and 115 (one hundred and fifteen) contains 20 letters. The use of “and” when writing out numbers is in compliance with British usage.

This problem required quit a bit more code than what we’ve done so far. I had to manually handle for each case of numbers, 1-19, and each interval of 10 (20, 30, 40, etc.) since they don’t follow a reusable rule. The cool thing is once those were taken care of, I could handle all numbers up to 9999.

I use one function for all numbers 1-19, and a main function that processes all numbers and calls the `handle_LT_twenty`

function when required.

DECLARE total INTEGER := 0; FUNCTION handle_LT_twenty(x INTEGER) RETURN INTEGER --handle "less than" twenty IS char_count INTEGER; BEGIN IF x IN (1,2,6,10) THEN char_count := 3; ELSIF x IN (4,5,9) THEN char_count := 4; ELSIF x IN (3,7,8) THEN char_count := 5; ELSIF x IN (11,12) THEN char_count := 6; ELSIF x IN (15,16) THEN char_count := 7; ELSIF x IN (13,14,18,19) THEN char_count := 8; ELSIF x IN (17) THEN char_count := 9; END IF; return char_count; END; FUNCTION count_chars(x INTEGER) RETURN INTEGER IS char_count INTEGER := 0; ones_digit INTEGER := SUBSTR(x,-1,1); -- right-most digit tens_digit INTEGER := SUBSTR(x,-2,1); hundreds_digit INTEGER := SUBSTR(x,-3,1); thousands_digit INTEGER := SUBSTR(x,-4,1); BEGIN --handle for cases of 19 and less IF tens_digit IN (1) OR length(x) < 2 THEN char_count := handle_LT_twenty(tens_digit||ones_digit); ELSE --handle the tens digit for 20 and higher IF tens_digit IN (2,3,8,9) THEN -- "twenty", "thirty", etc. char_count := 6; ELSIF tens_digit IN (4,5,6) THEN -- "forty", "fifty", etc. char_count := 5; ELSIF tens_digit IN (7) THEN -- "seventy" char_count := 7; END IF; IF ones_digit != 0 THEN char_count := char_count + handle_LT_twenty(ones_digit); END IF; END IF; IF length(x) >= 3 AND hundreds_digit != 0 THEN --dealing with hundreds char_count := char_count + handle_LT_twenty(hundreds_digit); --hundred digit follows same rules as single digit, "one" hundred IF tens_digit+ones_digit = 0 THEN char_count := char_count + length('hundred'); -- 100 = "onehundred" ELSE char_count := char_count + length('hundredand'); --no spaces! 101 = "onehundredandone" END IF; ELSIF length(x) = 4 THEN --dealing with thousands char_count := char_count + handle_LT_twenty(thousands_digit); --thousands digit follows same rules as single digit, "one" thousand IF hundreds_digit+tens_digit+ones_digit = 0 THEN char_count := char_count + length('thousand'); -- 1000 = "onethousand" ELSE char_count := char_count + length('thousandand'); --no spaces! 1001 = "onethousandandone" END IF; END IF; return char_count; END; BEGIN FOR i IN 1..1000 LOOP total := total + count_chars(i); END LOOP; dbms_output.put_line(total); END; --output: 21124

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