{"id":225,"date":"2026-03-07T23:51:29","date_gmt":"2026-03-07T15:51:29","guid":{"rendered":"https:\/\/www.resilence.cn\/?p=225"},"modified":"2026-03-07T23:51:29","modified_gmt":"2026-03-07T15:51:29","slug":"day-4-%e5%be%aa%e7%8e%af%e7%bb%93%e6%9e%84","status":"publish","type":"post","link":"https:\/\/www.resilence.cn\/?p=225","title":{"rendered":"Day-4-\u5faa\u73af\u7ed3\u6784"},"content":{"rendered":"<h1>Day 4: \u5faa\u73af\u7ed3\u6784<\/h1>\n<h2>\ud83c\udfaf \u5b66\u4e60\u76ee\u6807<\/h2>\n<ul>\n<li>\u7406\u89e3\u5faa\u73af\u7684\u6982\u5ff5\u548c\u4f5c\u7528<\/li>\n<li>\u638c\u63e1 for\u3001while\u3001do-while \u5faa\u73af<\/li>\n<li>\u5b66\u4f1a\u4f7f\u7528 break \u548c continue<\/li>\n<li>\u638c\u63e1 for&#8230;of \u548c for&#8230;in \u5faa\u73af<\/li>\n<li>\u4e86\u89e3\u5faa\u73af\u7684\u6700\u4f73\u5b9e\u8df5<\/li>\n<\/ul>\n<h2>\ud83d\udca1 \u6838\u5fc3\u6982\u5ff5<\/h2>\n<h3>\u4ec0\u4e48\u662f\u5faa\u73af\uff1f<\/h3>\n<p>\u5faa\u73af\u7528\u4e8e\u91cd\u590d\u6267\u884c\u76f8\u540c\u7684\u4ee3\u7801\u5757\u3002\u5c31\u50cf\uff1a<\/p>\n<ul>\n<li>&quot;\u7ed5\u64cd\u573a\u8dd15\u5708&quot;<\/li>\n<li>&quot;\u628a\u540d\u5355\u4e0a\u7684\u4eba\u9010\u4e00\u901a\u77e5&quot;<\/li>\n<\/ul>\n<h3>\u4e3a\u4ec0\u4e48\u9700\u8981\u5faa\u73af\uff1f<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u6ca1\u6709\u5faa\u73af\nconsole.log(&quot;\u7b2c1\u6b21&quot;);\nconsole.log(&quot;\u7b2c2\u6b21&quot;);\nconsole.log(&quot;\u7b2c3\u6b21&quot;);\n\/\/ ...\u91cd\u590d100\u6b21\uff1f\n\n\/\/ \u6709\u5faa\u73af\nfor (let i = 1; i &lt;= 100; i++) {\n    console.log(`\u7b2c${i}\u6b21`);\n}\n<\/code><\/pre>\n<h2>\ud83d\udcdd for \u5faa\u73af<\/h2>\n<h3>\u57fa\u672c\u8bed\u6cd5<\/h3>\n<pre><code class=\"language-javascript\">for (\u521d\u59cb\u5316; \u6761\u4ef6; \u8fed\u4ee3) {\n    \/\/ \u5faa\u73af\u4f53\n}\n\n\/\/ \u793a\u4f8b\uff1a\u6253\u53701-5\nfor (let i = 1; i &lt;= 5; i++) {\n    console.log(i);\n}\n<\/code><\/pre>\n<h3>\u6267\u884c\u987a\u5e8f<\/h3>\n<pre><code class=\"language-javascript\">for (let i = 1; i &lt;= 5; i++) {\n    console.log(i);\n}\n\n\/\/ \u987a\u5e8f\uff1a\n\/\/ 1. i = 1 (\u521d\u59cb\u5316)\n\/\/ 2. \u68c0\u67e5 i &lt;= 5 (\u6761\u4ef6)\n\/\/ 3. \u6267\u884c console.log(i)\n\/\/ 4. i++ (\u8fed\u4ee3)\n\/\/ 5. \u56de\u5230\u6b65\u9aa42\n<\/code><\/pre>\n<h2>\ud83d\udd04 while \u5faa\u73af<\/h2>\n<h3>\u57fa\u672c\u8bed\u6cd5<\/h3>\n<pre><code class=\"language-javascript\">while (\u6761\u4ef6) {\n    \/\/ \u5faa\u73af\u4f53\n}\n\n\/\/ \u793a\u4f8b\nlet i = 1;\nwhile (i &lt;= 5) {\n    console.log(i);\n    i++;\n}\n<\/code><\/pre>\n<h3>\u4f7f\u7528\u573a\u666f<\/h3>\n<p>\u5f53\u4e0d\u77e5\u9053\u5faa\u73af\u6b21\u6570\u65f6\u4f7f\u7528\u3002<\/p>\n<pre><code class=\"language-javascript\">\/\/ \u7b49\u5f85\u7528\u6237\u8f93\u5165\u6b63\u786e\u503c\nlet input;\nwhile (input !== &quot;quit&quot;) {\n    input = prompt(&quot;\u8f93\u5165\u547d\u4ee4\uff08quit\u9000\u51fa\uff09&quot;);\n}\n<\/code><\/pre>\n<h2>\ud83d\udd01 do-while \u5faa\u73af<\/h2>\n<pre><code class=\"language-javascript\">do {\n    \/\/ \u5faa\u73af\u4f53\n} while (\u6761\u4ef6);\n\n\/\/ \u793a\u4f8b\uff1a\u81f3\u5c11\u6267\u884c\u4e00\u6b21\nlet input;\ndo {\n    input = prompt(&quot;\u8f93\u5165\u4e00\u4e2a\u6b63\u6570&quot;);\n} while (input &lt;= 0);\n<\/code><\/pre>\n<p><strong>\u7279\u70b9<\/strong>\uff1a\u5faa\u73af\u4f53\u81f3\u5c11\u6267\u884c\u4e00\u6b21\u3002<\/p>\n<h2>\ud83c\udfaf for&#8230;of \u5faa\u73af<\/h2>\n<p>\u7528\u4e8e\u904d\u5386\u6570\u7ec4\u7684\u503c\u3002<\/p>\n<pre><code class=\"language-javascript\">const fruits = [&quot;\u82f9\u679c&quot;, &quot;\u9999\u8549&quot;, &quot;\u6a59\u5b50&quot;];\n\nfor (let fruit of fruits) {\n    console.log(fruit);\n}\n\n\/\/ \u8f93\u51fa\uff1a\n\/\/ \u82f9\u679c\n\/\/ \u9999\u8549\n\/\/ \u6a59\u5b50\n<\/code><\/pre>\n<h2>\ud83d\udd11 for&#8230;in \u5faa\u73af<\/h2>\n<p>\u7528\u4e8e\u904d\u5386\u5bf9\u8c61\u7684\u952e\u3002<\/p>\n<pre><code class=\"language-javascript\">const person = {\n    name: &quot;\u5f20\u4e09&quot;,\n    age: 25,\n    city: &quot;\u5317\u4eac&quot;\n};\n\nfor (let key in person) {\n    console.log(`${key}: ${person[key]}`);\n}\n\n\/\/ \u8f93\u51fa\uff1a\n\/\/ name: \u5f20\u4e09\n\/\/ age: 25\n\/\/ city: \u5317\u4eac\n<\/code><\/pre>\n<p><strong>\u6ce8\u610f<\/strong>\uff1a\u4e0d\u8981\u7528 for&#8230;in \u904d\u5386\u6570\u7ec4\uff01<\/p>\n<h2>\u23f9\ufe0f break \u548c continue<\/h2>\n<h3>break &#8211; \u8df3\u51fa\u5faa\u73af<\/h3>\n<pre><code class=\"language-javascript\">for (let i = 1; i &lt;= 10; i++) {\n    if (i === 5) {\n        break;  \/\/ \u8df3\u51fa\u5faa\u73af\n    }\n    console.log(i);  \/\/ \u53ea\u6253\u5370 1,2,3,4\n}\n<\/code><\/pre>\n<h3>continue &#8211; \u8df3\u8fc7\u672c\u6b21<\/h3>\n<pre><code class=\"language-javascript\">for (let i = 1; i &lt;= 5; i++) {\n    if (i === 3) {\n        continue;  \/\/ \u8df3\u8fc7\u672c\u6b21\uff0c\u7ee7\u7eed\u4e0b\u4e00\u6b21\n    }\n    console.log(i);  \/\/ \u6253\u5370 1,2,4,5\n}\n<\/code><\/pre>\n<h2>\ud83c\udfae \u5b9e\u6218\u793a\u4f8b<\/h2>\n<h3>\u793a\u4f8b1\uff1a\u8ba1\u7b97\u6570\u7ec4\u548c<\/h3>\n<pre><code class=\"language-javascript\">function sumArray(numbers) {\n    let sum = 0;\n    for (let num of numbers) {\n        sum += num;\n    }\n    return sum;\n}\n\nconsole.log(sumArray([1, 2, 3, 4, 5]));  \/\/ 15\n<\/code><\/pre>\n<h3>\u793a\u4f8b2\uff1a\u67e5\u627e\u6700\u5927\u503c<\/h3>\n<pre><code class=\"language-javascript\">function findMax(numbers) {\n    let max = numbers[0];\n    for (let num of numbers) {\n        if (num &gt; max) {\n            max = num;\n        }\n    }\n    return max;\n}\n<\/code><\/pre>\n<h3>\u793a\u4f8b3\uff1a\u8fc7\u6ee4\u6570\u7ec4<\/h3>\n<pre><code class=\"language-javascript\">function filterPositive(numbers) {\n    let result = [];\n    for (let num of numbers) {\n        if (num &gt; 0) {\n            result.push(num);\n        }\n    }\n    return result;\n}\n\nconsole.log(filterPositive([-1, 2, -3, 4, 0]));  \/\/ [2, 4]\n<\/code><\/pre>\n<h3>\u793a\u4f8b4\uff1a\u5d4c\u5957\u5faa\u73af\uff08\u4e58\u6cd5\u8868\uff09<\/h3>\n<pre><code class=\"language-javascript\">function multiplicationTable() {\n    for (let i = 1; i &lt;= 9; i++) {\n        let row = &quot;&quot;;\n        for (let j = 1; j &lt;= i; j++) {\n            row += `${j}\u00d7${i}=${i*j} `;\n        }\n        console.log(row);\n    }\n}\n\n\/\/ \u8f93\u51fa\uff1a\n\/\/ 1\u00d71=1 \n\/\/ 1\u00d72=2 2\u00d72=4 \n\/\/ 1\u00d73=3 2\u00d73=6 3\u00d73=9 \n\/\/ ...\n<\/code><\/pre>\n<h3>\u793a\u4f8b5\uff1a\u6570\u7ec4\u67e5\u627e<\/h3>\n<pre><code class=\"language-javascript\">function findIndex(array, target) {\n    for (let i = 0; i &lt; array.length; i++) {\n        if (array[i] === target) {\n            return i;  \/\/ \u627e\u5230\u8fd4\u56de\u7d22\u5f15\n        }\n    }\n    return -1;  \/\/ \u6ca1\u627e\u5230\n}\n<\/code><\/pre>\n<h3>\u793a\u4f8b6\uff1a\u5bf9\u8c61\u904d\u5386<\/h3>\n<pre><code class=\"language-javascript\">function printObjectProperties(obj) {\n    for (let key in obj) {\n        if (obj.hasOwnProperty(key)) {  \/\/ \u68c0\u67e5\u662f\u5426\u662f\u81ea\u8eab\u5c5e\u6027\n            console.log(`${key}: ${obj[key]}`);\n        }\n    }\n}\n\nprintObjectProperties({\n    name: &quot;\u5f20\u4e09&quot;,\n    age: 25,\n    city: &quot;\u5317\u4eac&quot;\n});\n<\/code><\/pre>\n<h2>\u270d\ufe0f \u7ec3\u4e60\u4efb\u52a1<\/h2>\n<h3>\u7ec3\u4e601\uff1a\u8ba1\u7b97\u9636\u4e58<\/h3>\n<pre><code class=\"language-javascript\">function factorial(n) {\n    let result = 1;\n    for (let i = 2; i &lt;= n; i++) {\n        result *= i;\n    }\n    return result;\n}\n\nconsole.log(factorial(5));  \/\/ 120\nconsole.log(factorial(10)); \/\/ 3628800\n<\/code><\/pre>\n<h3>\u7ec3\u4e602\uff1a\u53cd\u8f6c\u6570\u7ec4<\/h3>\n<pre><code class=\"language-javascript\">function reverseArray(arr) {\n    let reversed = [];\n    for (let i = arr.length - 1; i &gt;= 0; i--) {\n        reversed.push(arr[i]);\n    }\n    return reversed;\n}\n\nconsole.log(reverseArray([1, 2, 3, 4, 5]));  \/\/ [5, 4, 3, 2, 1]\n<\/code><\/pre>\n<h3>\u7ec3\u4e603\uff1a\u7edf\u8ba1\u5b57\u7b26\u51fa\u73b0\u6b21\u6570<\/h3>\n<pre><code class=\"language-javascript\">function countCharacters(str) {\n    let count = {};\n    for (let char of str) {\n        count[char] = (count[char] || 0) + 1;\n    }\n    return count;\n}\n\nconsole.log(countCharacters(&quot;hello&quot;));\n\/\/ {h: 1, e: 1, l: 2, o: 1}\n<\/code><\/pre>\n<h3>\u7ec3\u4e604\uff1a\u751f\u6210\u6590\u6ce2\u90a3\u5951\u6570\u5217<\/h3>\n<pre><code class=\"language-javascript\">function fibonacci(n) {\n    let sequence = [0, 1];\n    for (let i = 2; i &lt; n; i++) {\n        sequence[i] = sequence[i-1] + sequence[i-2];\n    }\n    return sequence.slice(0, n);\n}\n\nconsole.log(fibonacci(10));\n\/\/ [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]\n<\/code><\/pre>\n<h2>\ud83c\udf93 \u4eca\u65e5\u6311\u6218<\/h2>\n<p><strong>\u9879\u76ee\uff1a\u731c\u6570\u5b57\u6e38\u620f<\/strong><\/p>\n<pre><code class=\"language-javascript\">function guessNumber() {\n    const target = Math.floor(Math.random() * 100) + 1;\n    let attempts = 0;\n    \n    while (true) {\n        let guess = parseInt(prompt(&quot;\u731c\u4e00\u4e2a1-100\u7684\u6570\u5b57&quot;));\n        attempts++;\n        \n        if (guess === target) {\n            alert(`\u606d\u559c\uff01\u4f60\u7528\u4e86${attempts}\u6b21\u731c\u5bf9\u4e86\uff01`);\n            break;\n        } else if (guess &lt; target) {\n            alert(&quot;\u592a\u5c0f\u4e86\uff01&quot;);\n        } else {\n            alert(&quot;\u592a\u5927\u4e86\uff01&quot;);\n        }\n    }\n}\n<\/code><\/pre>\n<p><strong>\u6269\u5c55\u529f\u80fd<\/strong>\uff1a<\/p>\n<ol>\n<li>\u9650\u5236\u6700\u591a\u731c10\u6b21<\/li>\n<li>\u663e\u793a\u5386\u53f2\u731c\u6d4b\u8bb0\u5f55<\/li>\n<li>\u7ed9\u51fa\u8303\u56f4\u63d0\u793a<\/li>\n<\/ol>\n<h2>\u26a0\ufe0f \u5e38\u89c1\u9519\u8bef<\/h2>\n<h3>1. \u65e0\u9650\u5faa\u73af<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u274c \u5fd8\u8bb0\u8fed\u4ee3\nlet i = 0;\nwhile (i &lt; 10) {\n    console.log(i);\n    \/\/ \u5fd8\u8bb0 i++\n}\n\n\/\/ \u2705 \u6b63\u786e\nlet i = 0;\nwhile (i &lt; 10) {\n    console.log(i);\n    i++;\n}\n<\/code><\/pre>\n<h3>2. \u5faa\u73af\u6761\u4ef6\u9519\u8bef<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u274c \u5e94\u8be5\u662f &lt;=\nfor (let i = 0; i &lt; 10; i++) {\n    console.log(i);  \/\/ \u53ea\u6253\u5370\u52309\n}\n\n\/\/ \u2705 \u5305\u542b10\nfor (let i = 0; i &lt;= 10; i++) {\n    console.log(i);  \/\/ \u6253\u5370\u523010\n}\n<\/code><\/pre>\n<h3>3. \u6df7\u6dc6 for&#8230;of \u548c for&#8230;in<\/h3>\n<pre><code class=\"language-javascript\">const arr = [10, 20, 30];\n\n\/\/ \u274c \u9519\u8bef\uff1afor...in \u904d\u5386\u7d22\u5f15\nfor (let i in arr) {\n    console.log(i);  \/\/ &quot;0&quot;, &quot;1&quot;, &quot;2&quot;\n}\n\n\/\/ \u2705 \u6b63\u786e\uff1afor...of \u904d\u5386\u503c\nfor (let num of arr) {\n    console.log(num);  \/\/ 10, 20, 30\n}\n<\/code><\/pre>\n<h2>\ud83d\udca1 \u6700\u4f73\u5b9e\u8df5<\/h2>\n<h3>1. \u4f18\u5148\u4f7f\u7528 for&#8230;of<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u2705 \u66f4\u6e05\u6670\nfor (let item of array) {\n    console.log(item);\n}\n\n\/\/ \u274c \u4f20\u7edf\u65b9\u5f0f\nfor (let i = 0; i &lt; array.length; i++) {\n    console.log(array[i]);\n}\n<\/code><\/pre>\n<h3>2. \u907f\u514d\u6df1\u5c42\u5d4c\u5957<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u274c \u96be\u8bfb\nfor (let i = 0; i &lt; 10; i++) {\n    for (let j = 0; j &lt; 10; j++) {\n        for (let k = 0; k &lt; 10; k++) {\n            \/\/ ...\n        }\n    }\n}\n\n\/\/ \u2705 \u63d0\u53d6\u51fd\u6570\nfunction processItem(item) {\n    \/\/ \u5904\u7406\u903b\u8f91\n}\n\nfor (let item of items) {\n    processItem(item);\n}\n<\/code><\/pre>\n<h3>3. \u4f7f\u7528\u6570\u7ec4\u65b9\u6cd5\u66ff\u4ee3\u5faa\u73af<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u4f20\u7edf\u65b9\u5f0f\nlet doubled = [];\nfor (let num of numbers) {\n    doubled.push(num * 2);\n}\n\n\/\/ \u73b0\u4ee3\u65b9\u5f0f\nlet doubled = numbers.map(num =&gt; num * 2);\n<\/code><\/pre>\n<h2>\ud83d\udcda \u5faa\u73af\u5e94\u7528\u573a\u666f<\/h2>\n<h3>1. \u6570\u636e\u5904\u7406<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u5904\u7406\u7528\u6237\u5217\u8868\nusers.forEach(user =&gt; {\n    user.fullName = `${user.firstName} ${user.lastName}`;\n});\n<\/code><\/pre>\n<h3>2. \u641c\u7d22\u548c\u67e5\u627e<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u67e5\u627e\u7279\u5b9a\u5143\u7d20\nconst found = products.find(p =&gt; p.id === targetId);\n<\/code><\/pre>\n<h3>3. \u6570\u636e\u8f6c\u6362<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u8f6c\u6362\u6570\u636e\u683c\u5f0f\nconst formatted = data.map(item =&gt; ({\n    id: item.id,\n    name: item.name.toUpperCase()\n}));\n<\/code><\/pre>\n<h3>4. \u7d2f\u8ba1\u8ba1\u7b97<\/h3>\n<pre><code class=\"language-javascript\">\/\/ \u8ba1\u7b97\u603b\u4ef7\nconst total = cartItems.reduce((sum, item) =&gt; {\n    return sum + item.price * item.quantity;\n}, 0);\n<\/code><\/pre>\n<hr>\n<p><strong>\u5b66\u4e60\u65f6\u95f4<\/strong>: 2026-03-07 13:30<br \/>\n<strong>\u96be\u5ea6<\/strong>: \u2b50\u2b50\u2b50\u2606\u2606<br \/>\n<strong>\u9884\u8ba1\u7528\u65f6<\/strong>: 2-3 \u5c0f\u65f6<br \/>\n<strong>\u5173\u952e\u8bcd<\/strong>: \u5faa\u73af, for, while, break, continue<br \/>\n<strong>\u76f8\u5173\u6807\u7b7e<\/strong>: #03-\u63a7\u5236\u6d41<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Day 4: \u5faa\u73af\u7ed3\u6784 \ud83c\udfaf \u5b66\u4e60\u76ee\u6807 \u7406\u89e3\u5faa\u73af\u7684\u6982\u5ff5\u548c\u4f5c\u7528 \u638c\u63e1 for\u3001while\u3001do-while \u5faa\u73af  &#8230; <a title=\"Day-4-\u5faa\u73af\u7ed3\u6784\" class=\"read-more\" href=\"https:\/\/www.resilence.cn\/?p=225\" aria-label=\"\u7ee7\u7eed\u9605\u8bfbDay-4-\u5faa\u73af\u7ed3\u6784\">\u9605\u8bfb\u66f4\u591a<\/a><\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-225","post","type-post","status-publish","format-standard","hentry","category-studycoding"],"_links":{"self":[{"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/posts\/225","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=225"}],"version-history":[{"count":1,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/posts\/225\/revisions"}],"predecessor-version":[{"id":226,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=\/wp\/v2\/posts\/225\/revisions\/226"}],"wp:attachment":[{"href":"https:\/\/www.resilence.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=225"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=225"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.resilence.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=225"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}