Use PHP + MYSQL to create a powerful online calculator

Last Update:2018-12-08 Source: Internet

Author: User

Tags acos asin natural logarithm

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After searching for a long time, I found that there was very little information on the Internet, so I wanted to write it myself. I slowly found that there were many problems and I was not very familiar with it. Algorithm It's okay to write a computing formula. If it's longer, it's okay. If it's longer, I'm afraid it will crash.

One day when I was doing MySQL, I suddenly found that MySQL was so powerful that I could directly compute strings... Haha.

CodeIt's also a simple Ajax calculator.

You can also display input sub-statements at any time when a suberror is prompted.

If you are interested, you can develop more functions by yourself.

Demo address: http://www.jianlila.com/jsq.php

Download jquer. js by yourself

Jsq1.php Copy code The Code is as follows: <? PHP
// Link to the database
$ Db = mysql_connect ("localhost", "root", "123 ");
Header ("Content-Type: text/html; charset = gb2312 ");
$ STR = iconv ('utf-8', 'gbk', trim ($ _ post ['t _ ask ']);
$ STR = str_replace ("", "", str_replace ("\ r \ n", "", $ Str ));
$ STR = str_replace ("(", "(", $ Str );
$ STR = str_replace (")", ")", $ Str );
/* Trigonometric function replacement */
$ STR = preg_replace ("/sin $(. *) $/is "," Sin (\ $ {1} * Pi ()/180) ", $ Str); // replace sin
$ STR = preg_replace ("/COS $(. *) $/is "," cos (\ $ {1} * Pi ()/180) ", $ Str); // replace cos
$ STR = preg_replace ("/tan $(. *) $/is "," Tan (\ $ {1} * Pi ()/180) ", $ Str); // replace Tan
$ STR = preg_replace ("/COT $(. *) $/is "," 1/TAN (\ $ {1} * Pi ()/180) ", $ Str); // Replace the cotangent
$ STR = preg_replace ("/asin $(. *) $/is "," asin (\ $ {1}/PI () * 180) * 180/PI () ", $ Str); // returns the arc sine.
$ STR = preg_replace ("/ACOs $(. *) $/is "," ACOs (\ $ {1}/PI () * 180) * 180/PI () ", $ Str); // returns the arc cosine
$ STR = preg_replace ("/atan $(. *) $/is "," atan (\ $ {1}/PI () * 180) * 180/PI () ", $ Str); // Replace the arc tangent
$ SQL = "select". $ STR;
$ Res = mysql_query ($ SQL, $ dB) or die ('<font color = Red> the formula you entered has an error </font> ');
$ Rs = mysql_fetch_array ($ res );
Echo $ Rs [0];
?>

Jsq. php Copy code The Code is as follows: <HTML>
<Head>
<Title> handwritten input calculator </title>
<Meta name = "keywords" content = "online calculator, input formula, and handwritten calculator"/>
<Meta name = "Description" content = "online calculator, handwritten input calculator, input formula, and direct calculation"/>
<SCRIPT src = "jquery. js" Language = "JavaScript"> </SCRIPT>
<Script language = "JavaScript">
$ (Function (){
$ ("# T_ask"). keyup (function (){
$. Post (
"Jsq1.php ",
{
T_ask: $ ("# t_ask"). Val ()
}, Function (data, textstatus)
{
$ ("# Res" pai.html (data );
}
);
});
});
</SCRIPT>
</Head>
<Body>
<Table width = "800" border = "0" align = "center" cellpadding = "0" cellspacing = "0">
<Tr>
<TD align = "center" Height = "40"> <H2> handwritten input calculator </H2> </TD>
</Tr>
</Table>
<Table width = "800" border = "0" align = "center" cellpadding = "0" cellspacing = "0">
<Tr>
<TD Height = "34" align = "center"> here you can write a subcomputation. Try again later! <A href = "http://www.jianlila.com"> back to home </a> </TD>
</Tr>
</Table>

<Form method = "Post">
<Table width = "800" border = "0" align = "center" cellpadding = "0" cellspacing = "0">
<Tr>
<TD width = "27%" align = "right"> formula: </TD>
<TD width = "73%"> <textarea name = "t_ask" Cols = "60" rows = "6" id = "t_ask"> </textarea> </TD>
</Tr>
<Tr>
<TD Height = "23" align = "right" >=</TD>
<TD> <Div id = "res"> </div> </TD>
</Tr>
<Tr>
<TD Height = "31" align = "right"> </TD>
<TD> <input type = "button" name = "TJ" id = "TJ" value = "button"/>
<Input type = "reset" name = "QC" id = "QC" value = "reset"/> </TD>
</Tr>
</Table>
<Table width = "800" border = "0" align = "center" cellpadding = "0" cellspacing = "0">
<Tr>
<TD> <p> Note: <br/>
Trigonometric function:
<P> sin (60) sine cos (60) cosine Tan (60) tangent Cot (60) cotangent
<P> asin (0.5) arcsin ACOs (0.5)
Arccosine atan (0.5) arc tangent
<P> ABS (-1) = 1 absolute value Ceil (0.1) = 1 first
<P> exponential logarithm
<P> exp (float Arg) // calculate the <strong> E </strong> (base of natural logarithm) Exponent
<P> log (10,100) = 2 // natural logarithm POW (2, 4) = 16 exponent SQRT (4) = 2 square root
<P> <br/>
</TD>
</Tr>
</Table>
</Form>
</Body>
</Html>

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