return num * num + test(num-1);
为什么return后面还有加上num * num;
好像没有什么意义?
但在教程里是这样写的!
我把num * num + 删掉也一样正常执行. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content=""> <script type="text/javascript"> function test(num){
document.write("<strong>输出的数字是:</strong>" + num + "<br />");
if(num ==1){
return 1;
}
else{
return num * num + test(num-1);
}
}</script>
</head> <body>
<script type="text/javascript">
var num = prompt("请输入1-10之间的数字:","");
test(num);
</script>
</body>
</html>
为什么return后面还有加上num * num;
好像没有什么意义?
但在教程里是这样写的!
我把num * num + 删掉也一样正常执行. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content=""> <script type="text/javascript"> function test(num){
document.write("<strong>输出的数字是:</strong>" + num + "<br />");
if(num ==1){
return 1;
}
else{
return num * num + test(num-1);
}
}</script>
</head> <body>
<script type="text/javascript">
var num = prompt("请输入1-10之间的数字:","");
test(num);
</script>
</body>
</html>
return num * num + test(num-1) 计算1——num的平方和
function test(num){
document.write("<strong>输出的数字是:</strong>" + num + "<br />");
if(num ==1){
return 1;
}
else{
return num * num + test(num-1);
}
}
var result = test(5);
document.write(result); // 55把num * num + 删掉也一样正常执行.
——确实没错,但是当输入为正整数时输出结果始终为 1。另,输入非正整数时即为死循环!
<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content=""> <script type="text/javascript"> function test(num){
document.write("<strong>输出的数字是:</strong>" + num + "<br />");
if(num ==1){
return 1;
}
else{
return num*num+test(num-1);
}
}</script>
</head> <body>
<script type="text/javascript">
var num = prompt("请输入1-10之间的数字:","");
document.write("1到"+num+"的平方和是:"test(num));
</script> </body>
</html>