Question

我有这段代码，基本上如果函数“minmax”里面的代码中的“IF”语句为真，我希望程序从头开始。我不确定如何实现这个逻辑，有人可以帮助

<?php 
// user to enter the number of heads
echo "Enter the number of heads: " . PHP_EOL;
// the script will wait here until the user has entered something and hit ENTER
$inhead = read_stdin();
// user to enter the number of legs
echo "Enter the number of legs: " . PHP_EOL;
// the script will wait here until the user has entered something and hit ENTER
$inleg = read_stdin();
function read_stdin()
{
    $fr=fopen("php://stdin","r");   // open our file pointer to read from stdin
    $input = fgets($fr,128);        // read a maximum of 128 characters
    $input = rtrim($input);         // trim any trailing spaces.
    fclose ($fr);                   // close the file handle
    return $input;                  // return the text entered
}
//function to evalute if th euser has provided the right number of legs
function minmax($number)
{
    global $inhead,$inleg;
    $min = 2*$inhead;
    $max = 4*$inhead;
    if ($number<$min || $number>$max)
    {
        echo "please enter a number between $min and $max to get the correct result";
        echo "\n";
        echo "\n";
    }
}

//function to calculate the number of heads and legs
function get_the_result($noofheads,$nooflegs)
{   
    $x=($nooflegs-(2*$noofheads))/2;
    $y=$noofheads - $x;
    echo "The num of dogs are $x";
    //echo "/n";
    echo "The no of humans are $y";
}
minmax($inleg);
get_the_result($inhead,$inleg);
?>

Answer 1

您可以使用goto：

location:
//...
goto location;

在您的情况下，您需要检查函数是否存在，不要尝试使用function_exists声明它们两次。

虽然这是可能的，但我建议您重写代码，因为这种方法显然是不可行的。

Answer 2

如果您的验证不满意，为什么不重新加载页面？尝试使用Session来显示错误消息。

<?php
session_start();
if(isset($_SESSION['error'])){
   echo $_SESSION['error'];
   unset($_SESSION['error']);
}

// user to enter the number of heads
echo "Enter the number of heads: " . PHP_EOL;
// the script will wait here until the user has entered something and hit ENTER
$inhead = read_stdin();
// user to enter the number of legs
echo "Enter the number of legs: " . PHP_EOL;
// the script will wait here until the user has entered something and hit ENTER
$inleg = read_stdin();
function read_stdin()
{
$fr=fopen("php://stdin","r");   // open our file pointer to read from stdin
$input = fgets($fr,128);        // read a maximum of 128 characters
$input = rtrim($input);         // trim any trailing spaces.
fclose ($fr);                   // close the file handle
return $input;                  // return the text entered
}
//function to evalute if th euser has provided the right number of legs
function minmax($number)
{
global $inhead,$inleg;
$min = 2*$inhead;
$max = 4*$inhead;

if ($number<$min || $number>$max)
{
    $_SESSION['error'] = "please enter a number between $min and $max to get the correct result";
    echo("<meta http-equiv='refresh' content='1'>");

}
}
//function to calculate the number of heads and legs
function get_the_result($noofheads,$nooflegs)
{   
$x=($nooflegs-(2*$noofheads))/2;
$y=$noofheads - $x;
echo "The num of dogs are $x";
//echo "/n";
echo "The no of humans are $y";
}
minmax($inleg);
get_the_result($inhead,$inleg);
?>

请注意，此处不能使用标头重新加载，因为某些元素已被回显。并且您可以更改内容的值以延迟页面重新加载的时间（值以秒为单位）。

如果condition为true，则转到程序的开头

2 个答案: