{"id":3582,"date":"2020-05-02T23:35:41","date_gmt":"2020-05-02T14:35:41","guid":{"rendered":"https:\/\/katblog.manadream.net\/?p=3582"},"modified":"2020-09-30T00:07:07","modified_gmt":"2020-09-29T15:07:07","slug":"lets-calculate","status":"publish","type":"post","link":"https:\/\/katblog.manadream.net\/index.php\/2020\/05\/02\/lets-calculate\/","title":{"rendered":"[PHP]Let’s Calculate![Programming for Kids and Above #3]"},"content":{"rendered":"

Hello, I’m kat, the manager of ‘kat’s blog.<\/p>\n

‘For the third installment of [Programming for Kids and Above], we will cover how to add, subtract, multiply, and divide in programming.<\/p>\n

Calculations are the specialty of computers.<\/span><\/p>\n

Even calculations that would take a long time for a human to solve, computers can do it in an instant.<\/span><\/p>\n\n\n

Why are computers fast?<\/h2>\n\n\n

Why is it that computers are so fast at doing calculations?<\/p>\n

That is because, there is electricity flowing inside the computer, and that electricity is doing the calculations such as addition.<\/p>\n

It is said that the speed of electricity is the same as the speed of light, and it is so fast that it cannot be seen by the naked eye.<\/p>\n

This speed enables it to do calculations in an instant.<\/p>\n\n\n

What we will use this time<\/strong><\/h2>\n\n\n

The programming language we will use this time<\/div>

<\/p>\n

This time we will use the following programming language to write out a program.<\/p>\n

\n

\u30fbPHP<\/p>\n<\/div>\n

<\/p><\/div><\/p>\n\n\n

Let’s calculate!<\/h2>\n\n\n

Let’s go ahead and write out a program.<\/p>\n

This time, we will be programming on a website called ‘paiza.’<\/p>\n

First, let’s display the website by clicking the link below.<\/p>\n

paiza website<\/a><\/span><\/span><\/p>\n

Once the website is displayed, check to make sure that the button on the top left is showing as ‘PHP.’<\/p>\n

If it hasn’t changed, choose ‘PHP.’<\/p>\n

\"\"<\/p>\n

Once you reach this stage, you are ready for the programming.<\/p>\n\n\n

Addition<\/h2>\n\n\n

After writing in the source code, click the ‘Run (Ctrl-Enter)’ button like the following image.<\/p>\n

Then the result will be displayed.<\/p>\n\n

\n<?php\n  \n \/\/ addition\n $result = 1 + 2;\n echo 'calculation result\uff1a' . $result;\n<\/pre><\/div>\n\n
Once you are done entering the necessary information, click the ‘Run’ button on the bottom left.<\/p>\n
\"\"<\/p>\n
If letters saying, ‘calculation result:3’ appear, then it is a success!<\/p>\n
Let me give a brief explanation about the program.<\/p>\n
~Explanation 1~<\/div>
<\/p>\n\n
\n<?php\n<\/pre><\/div>\n\n
This means the start of a PHP program.<\/p>\n
It is a rule to always put ‘<?php’ at the beginning of a PHP program.<\/p>\n
<\/p><\/div><\/p>\n
~Explanation 2~<\/div>
<\/p>\n\n
\n$result = 1 + 2;\n<\/pre><\/div>\n\n
Here, we will be adding numbers.<\/p>\n
‘$result’ is something that is called a variable.<\/p>\n
A variable is like a container, so you can put the value that is written after the ‘= (equal sign)’ into it.<\/p>\n
Here, we put the result (‘3’) of ‘1+2’ into the ‘$result’ variable (container).<\/p>\n
\u2713 Point<\/div>
<\/p>\n
In the case of PHP, there is a rule to always put a ‘$ (dollar)’ sign at the beginning of a variable<\/span>.<\/em><\/p>\n
You can decide freely which letters come after the ‘$’ sign.<\/em><\/p>\n
Let’s try making variables with a name of your choice such as, ‘$message,’ ‘$color.’<\/em><\/p>\n
<\/p><\/div>\n
<\/p><\/div><\/p>\n
~Explanation 3~<\/div>
<\/p>\n\n
\necho 'calculation result\uff1a' . $result;\n<\/pre><\/div>\n\n
Here, the calculation result is displayed on the screen.<\/p>\n
The letters written after ‘echo,’ will be displayed on the screen.<\/p>\n
The ‘.’ after ‘calculation result:’, is used to connect letters to letters (or variables).<\/p>\n
Here it is connecting ‘calculation result:’ , and ‘$result’.<\/p>\n
Because the calculation result from earlier (“”3″”) is in the ‘$result’, ‘calculation result:’ and ‘the value of $result(“”3″”)’ are connected, and ‘calculation result:3’ is displayed on the screen.<\/p>\n
<\/p><\/div><\/p>\n\n\n
Subtraction<\/h2>\n\n\n
Next, let’s try some subtractions.<\/p>\n
Enter the following into the source code input area.<\/p>\n\n
\n<?php\n\n \/\/ subtract\n $result = 3 - 2;\n echo 'calculation result\uff1a' . $result;\n<\/pre><\/div>\n\n
Once you finish entering, click the ‘Run’ button on the bottom left like we did with the addition calculations.<\/p>\n
If ‘calculation result:1’ is displayed, it is a success!<\/p>\n\n\n
Multiplication, Division<\/h2>\n\n\n
We follow the same steps for multiplication and division, but the symbols (operators) are different from what we are used to, so try to remember them.<\/p>\n
\n
\u25a0Operators for multiplication, division<\/p>\n
  Multiplication\u30fb\u30fb\u30fb’*’<\/p>\n
  Division\u30fb\u30fb\u30fb’\/’<\/p>\n<\/div>\n
Now, let’s make a program like the one shown below.<\/p>\n\n
\n<?php\n\n \/\/ multiply\n $result = 3 * 2;\n echo 'multiplication calculation result\uff1a' . $result . ',';\n  \n \/\/ divide\n $result = 4 \/ 2;\n echo 'division calculation result\uff1a' . $result;\n<\/pre><\/div>\n\n
It is a success if you click the ‘Run’ button and<\/p>\n
‘multiplication calculation result:6,division calculation result:2’<\/p>\n
is displayed.<\/p>\n
<\/i><\/div>
<\/p>\n
Don’t just stick to simple calculations, but try calculations which are more difficult, such as combining addition and multiplication.<\/em><\/p>\n
For example, what is the answer of 765 + 875 * 568 \u2013 23 \/ 54?<\/em><\/p>\n
A computer could give you the answer right away.<\/em><\/p>\n
<\/div><\/div><\/p>\n\n\n
Final thoughts<\/h2>\n\n\n
Calculation processes are written in pretty much all programs of machines.<\/p>\n
We’ll be using them a lot in this lecture series, so please try to remember how to write them out.<\/p>\n
Also, this time we only put one value in a variable, but next time I will explain how you can put multiple values into one variable, so please look forward to it!<\/p>\n
See you next time!<\/p>\n\n\n
\n\n\n\n
\n
\n
<<Proceed to previous article<\/a><\/div>\n\n\n\n
<\/p>\n<\/div>\n\n\n\n
\n
Proceed to next article>><\/a><\/div>\n\n\n\n
<\/p>\n<\/div>\n<\/div>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
Hello, I#8217;m kat, the manager of #8216;kat#8217;s blog. #8216;For the third installment of [Programming<\/p>\n","protected":false},"author":1,"featured_media":4083,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_locale":"ja","_original_post":"https:\/\/katblog.manadream.net\/?p=3582","_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[102],"tags":[107,108],"class_list":["post-3582","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-programming-lessons","tag-english","tag-programming","ja"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/katblog.manadream.net\/wp-content\/uploads\/2020\/05\/calculate.png","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paUgnN-VM","_links":{"self":[{"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/posts\/3582"}],"collection":[{"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/comments?post=3582"}],"version-history":[{"count":29,"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/posts\/3582\/revisions"}],"predecessor-version":[{"id":4085,"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/posts\/3582\/revisions\/4085"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/media\/4083"}],"wp:attachment":[{"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/media?parent=3582"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/categories?post=3582"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/katblog.manadream.net\/index.php\/wp-json\/wp\/v2\/tags?post=3582"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}