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How to implement arithmetic verification code in php

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Release： 2023-04-02 14:42:01

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This article mainly introduces the method of implementing arithmetic verification code in PHP. It has certain reference value. Now I share it with you. Friends in need can refer to it.

I have recently learned PHP. I also practiced the implementation of image functions and verification codes. Following the teacher’s advice, I wrote an arithmetic verification code function. It was the first time I completed a small exercise independently. I felt quite happy. However, I also knew my own limitations. , so I wrote it out specifically, hoping that the experts from all walks of life can give me some guidance and expand my horizons more

The php code is as follows: Implement the function of the verification code

<?php/**
 * @param int $width 宽度,默认为120
 * @param int $height 高度,默认为50
 * @param int $fontSize 字体的大小
 * @return 图片资源
 */function arithmeticCode($width=120,$height=50,$fontSize=20){
    //开启session
    session_start();    //创建画布
    $img = imagecreatetruecolor($width,$height);    //分配颜色
    $color = imagecolorallocate($img,255,255,255);    //填充颜色
    imagefill($img,0,0,$color);    //干扰点
    for ($i = 0;$i < 500;$i++){        $pixColor = imagecolorallocate($img,mt_rand(100,200),mt_rand(100,200),mt_rand(100,200));
        imagesetpixel($img,mt_rand(0,$width),mt_rand(0,$height),$pixColor);
    }    //干扰线
    for ($i = 0;$i < 4;$i++){        $lineColor = imagecolorallocate($img,mt_rand(0,120),mt_rand(0,120),mt_rand(0,120));
        imageline($img,mt_rand(0,$width),mt_rand(0,$height),mt_rand(0,$width),mt_rand(0,$height),$lineColor);
    }    //定义一个数组存放运算符号
    $arr = [&#39;+&#39;,&#39;-&#39;,&#39;*&#39;];    //计算数组的长度
    $len = count($arr);    //定义一个1到20的数组
    $num = range(1,20);    $numLen = count($num);    //定义一个空数组来存放随机取得的验证码
    $code = [];    for ($i = 0;$i < $len;$i++) {        if ($i == 1) {            $code[] = $arr[mt_rand(0,$len-1)];
        }else {            $code[] = $num[mt_rand(0,$numLen-1)];
        }
    }    $str = implode($code);//将数组转为字符串
    $textColor = imagecolorallocate($img,mt_rand(100,200),mt_rand(100,200),mt_rand(100,200));    $fontAngle = 0;    $x = ($width - $fontSize*3)/2;    $y = ($height - $fontSize) / 2 + $fontSize;
    imagettftext($img,$fontSize,$fontAngle,$x,$y,$textColor,"./img/msyh.ttc",$str);    $res = getRes($code);    //将函数存放在session中
    $_SESSION[&#39;res&#39;] = $res;    //输出图片
    header("content-type:image/png");
    imagepng($img);
}/**
 * @param $arr 一个包含运算符号的数组
 * @return 返回一个运算结果
 */function getRes($arr) {
    $sum = 0;    //判断数组元素下标为1的运算符号是什么
    switch ($arr[1]){        case &#39;+&#39;:            $sum = $arr[0] + $arr[2];            break;        case &#39;-&#39;:            $sum = $arr[0] - $arr[2];            break;        case &#39;*&#39;:            $sum = $arr[0] * $arr[2];            break;
    }    return $sum;
}//调用函数arithmeticCode(100,40,18);

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Part of the code of html

<!doctype html><html lang="en"><head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        img {            position: relative;            top: 20px;        }
    </style></head><body><form action="test.php">
    验证码 <input type="text" name="code">
    <img src="./demo5.php" alt="点击刷新">
    <br>
    <button>提交</button></form></body></html><script>
    //实现点击图片刷新验证码的功能
    var img = document.querySelector("img");
    img.onclick = function () {
        this.src = this.src+"?m="+Math.random();
    }</script>

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Test of test.php

<?phpsession_start();$res = $_SESSION[&#39;res&#39;];$value = $_GET[&#39;code&#39;];if ($res == $value) {    echo "test success";
}else{    echo "test fail";
}

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The above is the composition of my code.
I hope everyone can The great god is willing to teach you [Looking forward to the face]

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