<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
/**
* a+aa+aaa+...的和 a是数字
* @param num 指定循环的数字
* @param size 循环的次数 例如:2,22=20+2,222=200+22....
*/
function t4(a,count){
var sum =0, b=0
for(var i=1;i<count;i++){
b = b + a
sum = sum+b
a = a*10
}
return sum
}
console.log(t4(2,4))
</script>
</body>
</html>
<!
DOCTYPE
html>
<
html
lang=
"en">
<
head>
<
meta
charset=
"UTF-8">
<
meta
name=
"viewport"
content=
"width=device-width, initial-scale=1.0">
<
title>Document</
title>
</
head>
<
body>
<
script>
/**
* a+aa+aaa+...的和 a是数字
* @param num 指定循环的数字
* @param size 循环的次数 例如:2,22=20+2,222=200+22....
*/
function
t4(
a,
count){
var sum
=
0, b
=
0
for(
var i
=
1;i
<
count;i
++){
b
= b
+
a
sum
= sum
+b
a
=
a
*
10
}
return sum
}
console.
log(
t4(
2,
4))
</
script>
</
body>
</
html>