{"id":344,"date":"2015-11-17T15:48:16","date_gmt":"2015-11-17T19:48:16","guid":{"rendered":"http:\/\/www.tayloraliss.com\/blog\/?p=344"},"modified":"2015-11-17T23:27:10","modified_gmt":"2015-11-18T03:27:10","slug":"references-pointers","status":"publish","type":"post","link":"https:\/\/www.tayloraliss.com\/blog\/?p=344","title":{"rendered":"References & Pointers"},"content":{"rendered":"

This week our class has finally encountered pointers. I knew that it would be a challenging subject, so I’m trying to take it slow. There are a couple of questions I have been trying to resolve in my mind since encountering these two concepts. The first one is: what is the point of pointers?<\/p>\n

That’s where I discovered\u00a0this comment<\/a>\u00a0on reddit that I feel applies to both pointers and references:<\/p>\n

The best metaphor I’ve found for pointers are websites.<\/p>\n

You could copy and paste the contents of a website into a document and then send that to someone, or you can send a pointer (the URL) to them.<\/p>\n

The benefit of the pointer is if the site gets updated, you both see the changes, whereas if you send a pasted document, they will never see any changes.<\/p><\/blockquote>\n

If you just use the variable, it’s copying the whole contents of the variable. Whereas if you use a pointer\/reference, it’s sending a lot less data and using a lot less memory.<\/p>\n

Another\u00a0difficult questions I’ve been working on answering is what the difference is between pointers and references. For that answer, I went to StackOverflow<\/a>:<\/p>\n

Use reference wherever you can, pointers wherever you must.<\/p>\n

Avoid pointers until you can’t.<\/p>\n

The reason is that pointers make things harder to follow\/read, less safe and far more dangerous manipulations than any other constructs.<\/p>\n

So the rule of thumb is to use pointers only if there is no other choice.<\/p><\/blockquote>\n

I’m sure there is more to it than that, but feel that those cover the basics pretty well. Now for actually learning the syntax. I wrote a little program to help remind myself of the finer points:<\/p>\n

 int myInt;\r\n int *myPointer;\r\n myPointer = &myInt;\r\n *myPointer = 5;\r\n cout << \"myPointer points to address \" << myPointer << endl; \/\/outputs address\r\n cout << \"The value stored at that address is \" << *myPointer << endl; \/\/outputs 5\r\n\r\n \/\/An array name, without brackets and a subscript, actually represents the starting \r\n \/\/address of the array. This means that an array name is really a pointer.\r\n int myArray[] = { 10, 20, 30 };\r\n cout << *myArray << endl; \/\/outputs 10\r\n\r\n \/\/These two lines do the same thing:\r\n cout << myArray[1] << endl; \/\/outputs 20\r\n cout << *(myArray + 1) << endl; \/\/outputs 20\r\n\r\n \/\/This adds 1 to the first value in the array:\r\n cout << *myArray + 1 << endl; \/\/outputs 11\r\n\r\n int *arrayPoint; \/\/This is a pointer that points to an int (or an array of ints)\r\n arrayPoint = myArray; \/\/Assign it to an array to point to\r\n cout << *arrayPoint << endl; \/\/outputs 10\r\n arrayPoint++;\r\n cout << *arrayPoint << endl; \/\/outputs 20<\/pre>\n
I’ll add some more notes for pointers and references later.<\/p>\n","protected":false},"excerpt":{"rendered":"
This week our class has finally encountered pointers. I knew that it would be a challenging subject, so I’m trying to take it slow. There are a couple of questions I have been trying to resolve in my mind since encountering these two concepts. The first one is: what is the point of pointers? That’s […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-344","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.tayloraliss.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/344","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tayloraliss.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tayloraliss.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tayloraliss.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tayloraliss.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=344"}],"version-history":[{"count":10,"href":"https:\/\/www.tayloraliss.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/344\/revisions"}],"predecessor-version":[{"id":359,"href":"https:\/\/www.tayloraliss.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/344\/revisions\/359"}],"wp:attachment":[{"href":"https:\/\/www.tayloraliss.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=344"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tayloraliss.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=344"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tayloraliss.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=344"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}