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web js代码作业

article 2025/1/19 23:10:44

作业题目

1.菱形代码
2.求所有三位水仙花数（水仙花数就是:个位的立方➕十位的立方➕百位的立方＝这个数本身）
3.用循环求10！
4.用循环求10！+9！+8！……1！
5.假如一次只能走上一阶或者一下子蹦上两阶。现在一共有N阶台阶，请你计算一下从第0阶到第N阶共有几种走法。
6.一对小兔子，4个月能长大，长大以后每个月生一对小兔子，求第n个月有多少对兔子。

代码

1.菱形代码

<!DOCTYPE html>
<html lang="zh">
 <head>
  <meta charset="UTF-8">
  <title>Document</title>
 </head>
 <body>
  <script>
   //    *           
   //   ***            
   //  *****          
   // *******          
   //  *****          
   //   ***           
   //    *       
   // 层 1 2 3 4
   // 空 3 2 1 0
   // 星 1 3 5 7
   // star = current * 2 - 1
   // up_layer = math.floor(total_layer / 2) + 1
   // space =  up_layer - current

   layer = parseInt(prompt("请输入层数"))
   up_layer = Math.ceil(layer / 2)
   end_layer = Math.ceil(layer-up_layer)
   for (let i = 1; i <= up_layer; i++){
		str = ""
		space_num = up_layer - i;
		for(let j = 1;j <= space_num; j++){
			str += " "
		}
		star_num = i * 2 -1
		for(let j = 1; j <= star_num; j++){
			str += "*"
		}
		console.log(str)
   }
   for (let b = end_layer; b > 0; b--){
	   str = ""
	   space_num = end_layer - b + 1;
	   for(let j=1; j<=space_num;j++)
	   {
		   str += " "
	   }
	   star_num = b * 2 - 1
		for(let j = 1; j <= star_num; j++){
			str += "*"
		}
		console.log(str)	   
   }
  </script>
 </body>
</html>

2.求所有三位水仙花数（水仙花数就是:个位的立方➕十位的立方➕百位的立方＝这个数本身）

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			for (let i = 100; i <= 999; i++)
			{
				bai = parseInt(i / 100)
				shi = parseInt(i % 100 /10)
				ge = parseInt(i % 10)
				sum = bai ** 3 + shi ** 3 + ge ** 3
				
				if (sum == i)
				{
					console.log(i)
					console.log(bai,shi,ge,sum)
				}
				// if (i == 109)
				// {
				// 	break
				// }
				
			}
		</script>
	</body>
</html>

3.用循环求10！

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			function can(num){
				let sum = num
				for(let i = num - 1; i > 0; i--){
					sum *= i
				}
				return sum
			}
			
			console.log(can(10))
		</script>
	</body>
</html>

4.用循环求10！+9！+8！……1！

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			function can(num){
				let sum = num
				for(let i = num - 1; i > 0; i--){
					sum *= i
				}
				return sum
			}		
			let he = 0
			for(let sum = 10; sum > 0; sum--){
				he += can(sum)
				// console.log(can(sum))
				// console.log(he)
			}
			console.log(he)
		</script>
	</body>
</html>

5.假如一次只能走上一阶或者一下子蹦上两阶。现在一共有N阶台阶，请你计算一下从第0阶到第N阶共有几种走法。

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			function staircase(sum){
				if(sum == 1 || sum == 2){
					return sum
				}
				else if(sum > 2){
					return staircase(sum - 1) + staircase(sum - 2)
				}
				else{
					return -1
				}
			}
			
			let sum
			sum = window.prompt("请输入一共有多少阶台阶")
			console.log(staircase(sum))
		</script>
	</body>
</html>

6.一对小兔子，4个月能长大，长大以后每个月生一对小兔子，求第n个月有多少对兔子。

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
		   function rabbit(month){
			   let sum
			   if (month <= 4){
				   sum = 1
				   return sum
			   }
			   else{
				   sum = rabbit(month - 4) + rabbit(month - 1)
				   return sum
			   }
		   }
		   
		   let month
		   month = window.prompt("请输入有多少个月")
		   console.log(rabbit(month)) 
		</script>
	</body>
</html>