我一直试图制作一个具有给定范围的随机数发生器,认为它很容易,然后没有任何逻辑推理,随机数不受任何方式影响给定的最大和最小范围。请帮忙。这是代码:
<!DOCTYPE html>
<html>
<head>
<style>
.elements {
text-align: center;
}
.random {
margin-top: 100px;
width: 275px;
height: 200px;
font-size: 50px;
text-align: center;
}
.range {
margin: 35px 25px;
width: 100px;
height: 100px;
text-align: center;
font-size: 30px;
}
.generate {
margin-top: 50px;
width: 250px;
height: 35px;
font-size: 20px;
}
</style>
<script language="javascript" type="text/javascript">
function rand()
{
var max = document.getElementById("max").value;
var min = document.getElementById("min").value;
var output = document.getElementById("output");
var random = Math.floor(Math.random() * max + min);
output.value = random;
}
</script>
</head>
<body>
<div class="elements">
<input type="text" class="random" id="output">
<br>
<input type="button" class="generate" value="Generate random number" onclick="rand();">
<br>
<h1>Maximum Number</h1>
<input type="text" class="range" id="max">
<h1>Minimal Number</h1>
<input type="text" class="range" id="min">
</div>
</body>
</html>
您需要将Math.random()
乘以范围的长度,而不是乘以范围中的最大值。
const getRandom = (min, max) => Math.floor(Math.random() * (max - min + 1) + min);
Array.from({ length: 20 }, () => console.log(getRandom(0, 2)));
document.getElementById("max").value
是字符串,所以现在Math.random() * max + min
是float * string + string
,它将min值附加为字符串。 parseInt
将解决这个问题。Math.random() * max + min
不正确。 Math.random() * (max - min + 1) + min
是对的。添加一个代码块,检查生成的随机数是否落在指定的范围内。如果它不循环通过随机数生成,直到条件测试失败;
function rand() {
var max = document.getElementById("max").value;
var min = document.getElementById("min").value;
var output = document.getElementById("output");
var random = Math.floor(Math.random() * max + min);
while (random > max || random < min) {
random = Math.floor(Math.random() * max + min);
}
output.value = random;
}
.elements {
text-align: center;
}
.random {
margin-top: 100px;
width: 275px;
height: 200px;
font-size: 50px;
text-align: center;
}
.range {
margin: 35px 25px;
width: 100px;
height: 100px;
text-align: center;
font-size: 30px;
}
.generate {
margin-top: 50px;
width: 250px;
height: 35px;
font-size: 20px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="elements">
<input type="text" class="random" id="output">
<br>
<input type="button" class="generate" value="Generate random number" onclick="rand();">
<br>
<h1>Maximum Number</h1>
<input type="text" class="range" id="max">
<h1>Minimal Number</h1>
<input type="text" class="range" id="min">
之后,您可以将其值分配给输出。
使用此代码:
// the initial seed
Math.seed = 6;
// in order to work 'Math.seed' must NOT be undefined,
// so in any case, you HAVE to provide a Math.seed
Math.seededRandom = function(max, min) {
max = max || 1;
min = min || 0;
Math.seed = (Math.seed * 9301 + 49297) % 233280;
return Math.floor(min + (Math.seed / 233280) * (max - min));
}
var res = Math.seededRandom(100,-100)
console.log(res)
或者自己尝试一下
http://indiegamr.com/generate-repeatable-random-numbers-in-js/