Filtered Accumulator

This is the first thing I made in Scheme that really impressed me. This function is really flexible and allows me to accumulate values (add, subtract, multiply, whatever) in between a range. This function also provides a filter for accumulating only certain values (ones that met a condition). Here are some examples of this: (for definitions of this, inc, and always, see code)

(filter-accumulate + 0 0 10 this inc always) ;Sum of the first 10 digits
(filter-accumulate * 1 1 5 this inc always) ;Factorial of 5.
(filter-accumulate + 0 0 10 this inc (lambda (x) (not (= x 5))))
;Sum of the first 10 digits, not excluding 5

With this function, I was able to complete 4 distinct Project Euler questions (see code below). I was shocked at the flexibility of this thing.

For those of you who know how to use Scheme, please let me know how I can improve this code. Thanks :)

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closure

Posted 104 Days Ago

Hi, good one. You might want to have a look at srfi-1 FOLD. cheers

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Genetic Algorithm for solving the N-Queens problem
Converting from infix notation to prefix and postfix notation
Factoring numbers
Path Finding
Pre, in, post order traversal of a binary tree.

Splitting a list recursively in Scheme
Genetic Algorithm for solving the N-Queens problem
Converting from infix notation to prefix and postfix notation
Factoring numbers
Path Finding

Splitting a list recursively in Scheme
down the tree
Solving the N-Queens-Problem Part I
Factoring numbers
Filtered Accumulator