{"id":6293,"date":"2024-03-16T00:01:02","date_gmt":"2024-03-16T07:01:02","guid":{"rendered":"https:\/\/c-for-dummies.com\/blog\/?p=6293"},"modified":"2024-03-09T12:50:26","modified_gmt":"2024-03-09T20:50:26","slug":"squaring-a-value","status":"publish","type":"post","link":"https:\/\/c-for-dummies.com\/blog\/?p=6293","title":{"rendered":"Squaring a Value"},"content":{"rendered":"

The C language lacks an operator that squares a value or, more generally, raises a value to a specific power. To do so, use the pow()<\/em> function. Yet I’m finding the need for a square()<\/em> function as I explore some interesting and obscure mathematical thingies.
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\nIn my digital travels, I’ve seen a few “square” or “power” operators. Perhaps the most common is the caret, ^<\/code>, as in 2^5<\/code> which raises two to the fifth power. Remember that in C, the ^<\/code> is the bitwise exclusive OR operator.<\/p>\n

Another exponent operator I’ve seen is **<\/code> as in 2**5<\/code>, which raises two to the fifth. In C, **<\/code> is used to identify a pointer to a pointer (an array of pointers).<\/p>\n

The lack of an exponent operator in C means that programmers use the pow()<\/em> function to raise a value to a specific power:<\/p>\n

pow(2,5);<\/code><\/p>\n

The above statement raises two to the fifth power. It requires that you include the math.h<\/code> header file. On some systems, you must also remember to link in the math library (-lm<\/code>) on the command line.<\/p>\n

Squaring a value happens frequently in math. The way I often code it in C is to write alpha*alpha<\/code> as opposed to pow(alpha,2);<\/code> I would guess that alpha*alpha<\/code> probably calculates faster internally.<\/p>\n

The following code demonstrates both methods to square a value:<\/p>\n

2024_03_16-Lesson-a.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n#include <math.h>\r\n\r\nint main()\r\n{\r\n    int alpha = 5;\r\n\r\n    printf(\"Alpha = %d\\n\",alpha);\r\n    printf(\"Alpha squared is %d\\n\",alpha*alpha);\r\n    printf(\"Alpha squared is %.f\\n\",pow(alpha,2) );\r\n\r\n    return 0;\r\n}<\/pre>\n
Here is the output:<\/p>\n
Alpha = 5
\nAlpha squared is 25
\nAlpha squared is 25<\/code><\/p>\n
If I’m desperate for a square()<\/em> function, I could write one. But instead, I think it would be better and more nerdy to code a macro, as shown in this update to the code:<\/p>\n
2024_03_16-Lesson-b.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n#include <math.h>\r\n\r\n#define squared(a) a*a\r\n\r\nint main()\r\n{\r\n    int alpha = 5;\r\n\r\n    printf(\"Alpha = %d\\n\",alpha);\r\n    printf(\"Alpha squared is %d\\n\",alpha*alpha);\r\n    printf(\"Alpha squared is %.f\\n\",pow(alpha,2) );\r\n    printf(\"Alpha squared is %d\\n\",squared(alpha) );\r\n\r\n    return 0;\r\n}<\/pre>\n
The squared()<\/em> “function” is really a macro. It accepts an argument, represented as a<\/code> in the definition, then replaces it with a*a<\/code>:<\/p>\n
#define squared(a) a*a<\/code><\/p>\n
In the code, the final printf()<\/em> statement is translated by the precompiler to this:<\/p>\n
printf(\"Alpha squared is %d\\n\",squared(alpha*alpha) );<\/code><\/p>\n
The output is the same as the first printf()<\/em> statement. I don’t think the macro saves any time, but it does add to readability, which is what I wanted.<\/p>\n
Well, what I’d really want is an exponent operator, but that’s never going to happen in the C language.<\/p>\n","protected":false},"excerpt":{"rendered":"
Could the C language use a square()<\/em> function or operator? Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-6293","post","type-post","status-publish","format-standard","hentry","category-main"],"_links":{"self":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/6293","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6293"}],"version-history":[{"count":3,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/6293\/revisions"}],"predecessor-version":[{"id":6309,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/6293\/revisions\/6309"}],"wp:attachment":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6293"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6293"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6293"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}