将变量写入工作表PHP [重复]

Question

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Iam staring with PHP. I'm trying to enter data into the website, make some calculations, and write it on website

<p><input type="number" id="a" > Typa A value </input>  </p>
<p><input type="number" id="b" > Type B value   </input>  </p>
<p><input type="submit" id="c" value="c " > </button>

session_start(); 
if (isset($_POST['a'])) {      

$a=$_POST['a'];
$a=$_POST['b'];
$d= $a * $b 
echo $d; }

//how to type it on website?

</div>

Answer 1

don't confuse to declare variables.

First change your html to this:

<p><input type="number" name="a" > Typa A value </input>  </p>
<p><input type="number" name="b" > Type B value   </input>  </p>
<p><input type="submit" name ="c"> </button>

Change your php code to this:

  session_start(); 
if (isset($_POST['c'])) {      

$a=$_POST['a'];
$b=$_POST['b'];
$d= (int)$a * (int)$b;  

echo $d;
}

It is in simplest way.