<script>
1.声明累加数组
let arr = []
while (arr.length < 5){
let num = +prompt(`请输入第${arr.length + 1}个人有效年龄`)
// 判断是否有效
if( num > 0 && num < 100){
// 添加到数组
arr.push(num)
}
}
console.log(arr);
// 2. 打印输出人的的年龄 年龄 > 18
for(let i = 0; i <= arr.length; i++){
if(arr[i] > 18){
document.write(`已经成人的年龄是：${arr[i]} <br>`)
}
}
// 3.打印出所有人的总年龄（累加）
let ageSum = 0
for(let i = 0; i <= arr.lenht; i++){
ageSum += arr[i]
}
document.write(`所有人的年龄是：${ageSum} <br>`)
// 4.打印出所有人的平均年龄（累加）
let average = 0
average = ageSum / arr.length
document.write(`所有人的平均年龄是：${average} <br>`)
5.打印出最大年龄和最小年龄（最大值） 假设法
let max = arr[0]
let min = arr[0]
for(let i = 1; i < arr.length; i++){
if(max < arr[i]){
max = arr[i]
}
if(min > arr[i]){
min = arr[i]
}
}
document.write(`最大值是：${max} <br>`)
document.write(`最小值是：${min} <br>`)
5.打印出最大年龄和最小年龄（最大值） 排序法
arr.sort(function (a,b){
return a - b;
}) // 升序
let min = arr[0]
let max = arr[arr.length - 1]
</script>
<script>
// 找出数组中 元素为10的下标，有则打印该下标，没有则打印 - 1
let arr = [88, 20, 10, 100, 50]
let re = -1 // 用于存储结果,默认没有
for (let i = 0; i < arr.length; i++) {
if (arr[i] === 10) {
re = i //如果找到则把当前索引号赋值给 re， 如果没有找到，则默认的是 -1
break // 已经找到就退出
}
}
console.log(re)
</script>
<script>
// 遇到数组 先把遍历写出来!!!!!!!!!!!!!!!=> 访问数组里面的单元的值
let arr = [5, 8, 9, 2, 1, 5]
let sum = 0
for (let i = 0; i < arr.length; i ++) {
// sum = sum + item
sum += item
}
console.log(sum) // 30
</script>
<script>
let arr = [4, 9, 5, 20, 3, 11]
for (let i= 0; i < arr.length; i++) {
if (arr[i] > 5) {
sum += arr[i]
}
}
console.log(sum)
</script>
<script>
//5.使用for循环-求出班级里同学们平均年龄[15,19,21,33,18,24]
let arr = [15,19,21,33,18,24]
let ave = 0
for(let i = 0; i < arr.length; i++){
ave += arr[i]
}
let aver = ave / arr.length
document.write(aver)
</script>
<script>
// 6.计算[2,6,18,15,40]中能被3整除的偶数的和
let arr = [2,6,18,15,40]
let counts = 0
for(let i = 0; i < arr.length; i++){
if( arr[i] % 3 === 0 && arr[i] % 2 === 0){
counts += arr[i]
}
}
document.write(counts)
</script>
<script>
// 7.计算[2,6,18,15,40]中能被3整除的偶数的个数
let arr2 = [2,6,18,15,40]
let counts1 = 0
for(let i = 0; i < arr2.length; i++){
if( arr2[i] % 3 === 0 && arr2[i] % 2 === 0){
counts1++
}
}
document.write(counts1)
</script>
<script>
// 8.给一个数字数组，该数组中有很多数字0，将不为0的数据存入到一个新的数组中
let arr3 = [0,2,3,0,3,0,3,0,5,0]
let arr4 = []
for(let i = 0; i < arr3.length; i++){
if(arr3[i] !== 0){
arr4.push(arr3[i])
}
}
document.write(arr4)
</script>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>渲染图片案例</title>
<style>
* {
margin: 0;
padding: 0;
}
li {
list-style: none;
}
.box {
display: flex;
flex-wrap: wrap;
width: 540px;
margin: 20px auto;
}
.box li {
width: 100px;
height: 100px;
margin: 0 10px 10px 0;
}
.box li:nth-child(5n+1) {
margin-right: 0;
}
.box li img {
width: 100%;
height: 100%;
border: 2px solid #258DF2;
border-radius: 10px 0 10px 0;
}
</style>
</head>
<body>
<ul class="box">
<script>
let arr = [
'./images/1.webp',
'./images/2.webp',
'./images/3.webp',
'./images/4.webp',
'./images/5.webp',
'./images/6.webp',
'./images/7.webp',
'./images/8.webp',
'./images/9.webp',
'./images/10.webp',
'./images/11.webp',
'./images/12.webp',
'./images/13.webp',
'./images/14.webp',
'./images/15.webp',
'./images/16.webp',
'./images/17.webp',
'./images/18.webp',
'./images/19.webp',
'./images/20.webp'
]
let num = prompt('请输入显示的英雄个数1~20之间：')
for (let i = 0; i < num; i++) {
document.write(`
<li>
<img src="${arr[i]}" alt="">
</li>
`)
}
</script>
</ul>
</body>
</html>
