首頁猿問用JS求1！+2！+3！+20！的階乘

用JS求1！+2！+3！+20！的階乘

JavaScript

慕粉0931027254 2017-08-10 08:39:30

大神们，才学了两天js的菜鸟求问只用双层for循环求怎么做？

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7 回答

蜂之谷

TA貢獻(xiàn)564條經(jīng)驗獲得超863個贊

<script?type="text/javascript">
var?sum?=?0;
for(var?i=1;i<=20;i++){
	var?jie?=?1;
	for(var?j=1;j<=i;j++){
		jie?*=?j;
	}
	alert("第"+i+"個階乘："+jie)
	sum?+=?jie;
}
alert("和："+sum)
</script>

1 反對回復(fù) 2017-08-10

慕粉0931027254
謝謝^ω^

回復(fù) 2017-08-11

慕的地5204680

TA貢獻(xiàn)8條經(jīng)驗獲得超13個贊

//雙層for循環(huán)
var?dataArray?=?[1,2,3];
var?sum?=?0;
for?(var?i=0;?i<dataArray.length;?i++)?{
????var?result?=?1;
????for(var?j=1;?j<=dataArray[i];?j++)?{
????????result?*=?j;
????}
????sum?+=?result;
}
console.log(sum);
//利用arguments的callee方法，array的map和reduce方法
var?caculateFactorial?=?function(x)?{
????if?(x===0)?{
????????return?1;
????}?else?{
????????return?x*?arguments.callee(x-1);
????}
}
var?sumArrayFactorial?=?function(dataList){
????return?dataList.map(caculateFactorial).reduce((a,?b)?=>?a+b);
}
var?dataList?=?[1,2,3,4,5];
sumArrayFactorial(dataList);

反對回復(fù) 2017-08-11