{"id":4441,"date":"2020-11-08T00:01:44","date_gmt":"2020-11-08T08:01:44","guid":{"rendered":"https:\/\/c-for-dummies.com\/blog\/?p=4441"},"modified":"2020-11-07T08:47:34","modified_gmt":"2020-11-07T16:47:34","slug":"calculating-months-solution","status":"publish","type":"post","link":"https:\/\/c-for-dummies.com\/blog\/?p=4441","title":{"rendered":"Calculating Months – Solution"},"content":{"rendered":"

The task for this month’s Exercise<\/a> is to return the month number for a time_t<\/em> value. Effectively you extract the year and month, do some math, presto. Could it be this easy?
\n
\nThe key is to extract the month and year values from a time_t<\/em> variable passed to the monthcount()<\/em> function, as presented in the original post. And — this part is important — converting these values into their accurate representations.<\/p>\n

Remember, a time_t<\/em> variable stores years starting at 1901 and months starting with 0 for January. Here is my solution:<\/p>\n

2020_11-Exercise.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n#include <time.h>\r\n\r\nint monthcount(time_t date)\r\n{\r\n    struct tm *dstruct;\r\n    int months;\r\n\r\n    dstruct = localtime(&date);\r\n    \/* year is dstruct->tm_year + 1900 *\/<\/span>\r\n    \/* month is dstruct->tm_mon + 1 *\/<\/span>\r\n    months = (dstruct->tm_year+1900) * 12;\r\n    months += dstruct->tm_mon+1;\r\n\r\n    return(months);\r\n}\r\n\r\nint main()\r\n{\r\n    int month;\r\n    time_t now;\r\n\r\n    time(&now);                    \/* get the current date\/time *\/<\/span>\r\n    month = monthcount(now);    \/* calculate total number of months *\/<\/span>\r\n    printf(\"This month is number %d\\n\",month);\r\n\r\n    return(0);\r\n}<\/pre>\n
At Line 9, I use the localtime()<\/em> function to fill a tm<\/em> structure, dstruct<\/code>, with details from the time_t<\/em> value, date<\/code>.<\/p>\n
At Line 12, variable months<\/code> is calculated as the current year multiplied by 12: months = (dstruct->tm_year+1900) * 12;<\/code>. This value is increased by the current month value, plus one, to obtain the month count at Line 13. The result is returned at Line 15.<\/p>\n
Here is a sample run (for today, 8 November 2020):<\/p>\n
This month is number 24251<\/code><\/p>\n
In my PHP code, I used this value to compare with the timestamp on a post. If the timestamp’s monthcount()<\/em> return value was 2 less, the post isn’t listed. This technique is how I’m able to display only current posts. It’s a specific solution, but one that provided an interesting programming challenge.<\/p>\n
I hope your solution meets with a good result. It’s possible to extract such information directly from a time_t<\/em> value, though remember time_t<\/em> is a cumulative total of seconds and not a bit field.<\/p>\n","protected":false},"excerpt":{"rendered":"
The task for this month’s Exercise is to return the month number for a time_t value. Effectively you extract the year and month, do some math, presto. Could it be this easy?<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-4441","post","type-post","status-publish","format-standard","hentry","category-solution"],"_links":{"self":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/4441","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=4441"}],"version-history":[{"count":4,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/4441\/revisions"}],"predecessor-version":[{"id":4463,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/4441\/revisions\/4463"}],"wp:attachment":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4441"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4441"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4441"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}