Currency Converter Using PHP

StackOverflow https://stackoverflow.com/questions/22212349

题

I am new to PHP so i am not sure what i am doing wrong but it seems only last if statement is getting executed which is USD to USD no matter what currencies i pick.

I need to make it so it converts FROM and TO currency that i pick and the conversion gets displayed in the amount_output box. And that currencies and the mount i typed in remain in the results without getting reset.

Any help it greatly appreciated.

<?php                
$amount_input = filter_input(INPUT_POST, 'amount_input');
$currency1 = filter_input(INPUT_POST, 'currency1');
$currency2 = filter_input(INPUT_POST, 'currency2');

if ($currency1="CAD" AND $currency2="CAD")
{
    $amount_output = $amount_input*1.0;
}

if ($currency1="CAD" AND $currency2="EUR")
{
    $amount_output = $amount_input*0.624514066;
}       

if ($currency1="CAD" AND $currency2="GBP")
{
    $amount_output = $amount_input*0.588714763;
}       

if ($currency1="CAD" AND $currency2="USD")
{
    $amount_output = $amount_input*0.810307;
}       
if ($currency1="EUR" AND $currency2="CAD")
{
    $amount_output = $amount_input*1.601244959;
}

if ($currency1="EUR" AND $currency2="EUR")
{
    $amount_output = $amount_input*1.0;
}       

if ($currency1="EUR" AND $currency2="GBP")
{
    $amount_output = $amount_input*0.942676548;
}       

if ($currency1="EUR" AND $currency2="USD")
{
    $amount_output = $amount_input*1.2975;
}

if ($currency1="GBP" AND $currency2="CAD")
{
    $amount_output = $amount_input*1.698615463;
}

if ($currency1="GBP" AND $currency2="EUR")
{
    $amount_output = $amount_input*1.060809248;
}       

if ($currency1="GBP" AND $currency2="GBP")
{
    $amount_output = $amount_input*1.0;
}       

if ($currency1="GBP" AND $currency2="USD")
{
    $amount_output = $amount_input*1.3764;
} 

if ($currency1="USD" AND $currency2="CAD")
{
    $amount_output = $amount_input*1.234100162;
}

if ($currency1="USD" AND $currency2="EUR")
{
    $amount_output = $amount_input*0.772200772;
}       

if ($currency1="USD" AND $currency2="GBP")
{
    $amount_output = $amount_input*0.726532984;
}       

if ($currency1="USD" AND $currency2="USD")
{
    $amount_output = $amount_input*1.0;
} 
?> 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!--
To change this license header, choose License Headers in Project Properties.
To change this template file, choose Tools | Templates
and open the template in the editor.
-->
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>F/X Calculator</title>
    <link href="fxCalcStyles.css" rel="stylesheet" type="text/css" />

</head>
<body>        
    <h1>Money Banks F/X Calculator</h1>
    <hr></hr>
    <form action="fxCalc.php" method="post">                
        <select name="currency1">
            <option value="CAD">CAD</option>
            <option value="EUR">EUR</option>
            <option value="GBP">GBP</option>
            <option value="USD">USD</option>
        </select>
        <input name="amount_input" type="text"/>
        <select name="currency2">
            <option value="CAD">CAD</option>
            <option value="EUR">EUR</option>
            <option value="GBP">GBP</option>
            <option value="USD">USD</option>
        </select>
        <input name="amount_output" type="text" value="<?php echo $amount_output ?>" readonly="readonly"/>

        <br />

        <input type="submit" name="submit" value="Convert"></input>
        <input type="reset" name="reset" value="Reset"></input>

    </form>                        
</body>
</html>
有帮助吗？

解决方案

Since you’re new to PHP, I’m not trying to show you complicated ways for your currency converter. Right now you need to learn the basics and shouldn’t focus on making your code concise by using advanced strategies. Your code is a nice one and will work perfectly if two adjustments are made:

  1. Use == (comparison operator) instead of = (assignment operator) when you compare two values.
  2. Use an if/else if/else structure instead of a series of disjointed if structures.

Now your code becomes:

<?php
$amount_input = filter_input(INPUT_POST, 'amount_input');
$currency1 = filter_input(INPUT_POST, 'currency1');
$currency2 = filter_input(INPUT_POST, 'currency2');

if ($currency1 == "CAD" AND $currency2 == "CAD")
{
    $amount_output = $amount_input*1.0;
}

else if ($currency1 == "CAD" AND $currency2 == "EUR")
{
    $amount_output = $amount_input*0.624514066;
}       

else if ($currency1 == "CAD" AND $currency2 == "GBP")
{
    $amount_output = $amount_input*0.588714763;
}       

else if ($currency1 == "CAD" AND $currency2 == "USD")
{
    $amount_output = $amount_input*0.810307;
}       

else if ($currency1 == "EUR" AND $currency2 == "CAD")
{
    $amount_output = $amount_input*1.601244959;
}

else if ($currency1 == "EUR" AND $currency2 == "EUR")
{
    $amount_output = $amount_input*1.0;
}       

else if ($currency1 == "EUR" AND $currency2 == "GBP")
{
    $amount_output = $amount_input*0.942676548;
}       

else if ($currency1 == "EUR" AND $currency2 == "USD")
{
    $amount_output = $amount_input*1.2975;
}

else if ($currency1 == "GBP" AND $currency2 == "CAD")
{
    $amount_output = $amount_input*1.698615463;
}

else if ($currency1 == "GBP" AND $currency2 == "EUR")
{
    $amount_output = $amount_input*1.060809248;
}       

else if ($currency1 == "GBP" AND $currency2 == "GBP")
{
    $amount_output = $amount_input*1.0;
}       

else if ($currency1 == "GBP" AND $currency2 == "USD")
{
    $amount_output = $amount_input*1.3764;
} 

else if ($currency1 == "USD" AND $currency2 == "CAD")
{
    $amount_output = $amount_input*1.234100162;
}

else if ($currency1 == "USD" AND $currency2 == "EUR")
{
    $amount_output = $amount_input*0.772200772;
}       

else if ($currency1 == "USD" AND $currency2 == "GBP")
{
    $amount_output = $amount_input*0.726532984;
}       

else if ($currency1 == "USD" AND $currency2 == "USD")
{
    $amount_output = $amount_input*1.0;
} 
?>

Happy coding!

其他提示

Your script can look so much easier using arrays, and you won't get problems with so many instructions:

<?php                
                $amount_input = filter_input(INPUT_POST, 'amount_input');
                $currency1 = filter_input(INPUT_POST, 'currency1');
                $currency2 = filter_input(INPUT_POST, 'currency2');

                $currencies = array();
                $currencies['CAD'] = array(
                    'CAD' => 1,
                    'EUR' => 0.624514066,
                    'GBP' => 0.588714763,
                    'USD' => 0.810307
                );

                $amount_output = $amount_input*$currencies[$currency1][$currency2];

?>

This would be easier to maintain, base all currencies on the dollar then do the following :

$currency1    = filter_input(INPUT_POST, 'currency1');
$currency2    = filter_input(INPUT_POST, 'currency2');
$amount_input = filter_input(INPUT_POST, 'amount_input');

$currencies = array(
    'USD' => 1,
    'CAD' => 1.234100162,
    'EUR' => 0.772200772,
    'GDP' => 0.726532984
);

$amount_output = ($amount_input/$currencies[$currency1])*$currencies[$currency2];
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