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copied!<blockquote> <p>Do we have any statements like "foreach", or for loop to do what i think? </p> </blockquote> <p>No.</p> <blockquote> <p>or any other suggestions?</p> </blockquote> <p>To iterate over a list in scheme, you'd either use pre-existing functions that iterate over the list (like <code>map</code>, <code>filter</code> or <code>fold-left</code>) or you write your own using recursion. Depending on which Scheme dialect you're using, there might already be a function (called <code>every</code> or <code>andmap</code>) that takes a list and a condition and returns <code>#t</code> iff the condition is true for every item in the list. Otherwise, you'd have to write it recursively or as a fold (though not all Scheme dialects have fold function either).</p> <p>A recursive function that iterates over a list usually looks something like this:</p> <pre><code>(define (do-something-with-list lst) (if (null? lst) (handle-the-case-that-list-is-empty) (combine (some-transformation-on (car lst)) (do-something-with-list (cdr lst))))) </code></pre> <p>For example to sum all numbers in a list that are greater than 5 (without using <code>filter</code> or <code>fold-left</code>), you'd write:</p> <pre><code>(define (sum-all-numbers>5 numbers) (if (null? numbers) ; Sum of the empty list is 0 0 (+ ; If the head of the list is > 5, add the number to the result, else ; add 0 (if (> (car numbers) 5) (car numbers) 0) (sum-all-numbers>5 (cdr numbers))))) </code></pre> <p>You can use the same approach to define your function.</p> <p>PS: <code>(if condition #t #f)</code> is redundant -- you can just write <code>condition</code> (unless <code>condition</code> is something other than a boolean and you need to convert it to a boolean, but I can't think of a scenario where that'd be necessary).</p>

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