computer-science

It occurred to me today that although I've adopted and don't infrequently use the term "semantics" when referring to language elements and naming conventions, I don't have any sense of a formal definition. My attempt to find a formal definition in the programming domain made my eyes glaze over. I have a sense of its meaning from the contexts in which I've encountered it, and from its more common usage with respect to linguistics, and I typically use the term to refer to the meaning or expressiveness of the language element, or the fidelity of nomenclature to the intent, behaviour, or function

I'm writing a tutorial to teach kids (ages 9 to 13) about programming. I started with computers themselves, they don't have that much to do with computer science, it's more about the process involved with a solution to a computational problem. With that starting point, I'm guiding them toward an understanding that machines can help us with certain computational problems. People are great at abstract thinking and imagination, but computers are AWESOME at following a well-specified routine. They can do it again and again, at amazing speed! Representing numbers in binary format has already been

I heard that hashing (ie converting a string or object to a number) is used for strings and such because it is easier to compare numbers than strings. If true, what is the reason for this ? This is not necessarily the case, but probably the case most of the time. Consider the following situation: I want to compare the string "apples" vs. "oranges". If I only want to determine "apples" == "oranges", I need only compare the first character of each string: 'a' != 'o' => "apples" != "oranges". If I hash the string and then do the comparison, it is significantly slower as I have to parse both