js 。 。。 。 。。

//求1-100之间所有偶数的和

考试，求答案

var num=100; var sum=0; for(var i=0;i<=num;i++){ if(i%2==0){ sum+=i; console.log(i) } } console.log("1-100所有偶数的和为:"+ sum);

结果为2550

<span class="hljs-built_in">var</span> <span class="hljs-built_in">num</span>=<span class="hljs-number">100</span>;
<span class="hljs-built_in">var</span> <span class="hljs-built_in">sum</span>=<span class="hljs-number">0</span>;
<span class="hljs-keyword">for</span>(<span class="hljs-built_in">var</span> i=<span class="hljs-number">0</span>;i<=<span class="hljs-built_in">num</span>;i++){
   <span class="hljs-keyword">if</span>(i%<span class="hljs-number">2</span>==<span class="hljs-number">0</span>){
      <span class="hljs-built_in">sum</span>+=i;
   }
}
console.<span class="hljs-built_in">log</span>(<span class="hljs-string">"1-100所有偶数的和为:"</span>+ <span class="hljs-built_in">sum</span>);

效果图：

<span class="hljs-keyword">let</span> <span class="hljs-keyword">sum</span> = <span class="hljs-number">0</span>
for ( <span class="hljs-keyword">let</span> i = <span class="hljs-number">1</span>; i <= <span class="hljs-number">100</span>; i++ ) {
    <span class="hljs-keyword">if</span> ( i % <span class="hljs-number">2</span> == <span class="hljs-number">0</span> ) {
    <span class="hljs-keyword">sum</span> += i
    }
}
console.<span class="hljs-keyword">log</span>( <span class="hljs-keyword">sum</span> )