java 泛型可变参数
有勇气的牛排
1066
Java
2021-08-26 21:57:34
1 可变参数介绍
可变参数又称参数个数可变,用作方法的形参出现,那么方法参数个数就是可变的了
格式:修饰符 返回值类型 方法名(数据类型…变量名){ }
范例:public static int sum(int…a){ }
可变参数注意事项:
2 代码
package itheima_06;
public class ArgsDemo01 {
public static void main(String[] args) {
System.out.println(sum(10, 20));
System.out.println(sum(10, 20, 30));
System.out.println(sum(10, 20, 30, 40));
}
public static int sum(int b, int... a) {
int sum = 0;
for (int i : a) {
sum += i;
}
return sum;
}
}
<h2><a id="1__0"></a>1 可变参数介绍</h2>
<p>可变参数又称参数个数可变,用作方法的形参出现,那么方法参数个数就是可变的了</p>
<p>格式:修饰符 返回值类型 方法名(数据类型…变量名){ }</p>
<p>范例:public static int sum(int…a){ }</p>
<p>可变参数注意事项:</p>
<ul>
<li>
<p>这里的变量其实是一个数组</p>
</li>
<li>
<p>如过一个方法有多个参数,包含可变参数,<strong>可变参数要放到后面</strong></p>
</li>
</ul>
<h2><a id="2__16"></a>2 代码</h2>
<pre><div class="hljs"><code class="lang-java"><span class="hljs-keyword">package</span> itheima_06;
<span class="hljs-comment">/**
* 测试类
*/</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">ArgsDemo01</span> {
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">main</span><span class="hljs-params">(String[] args)</span> {
System.out.println(sum(<span class="hljs-number">10</span>, <span class="hljs-number">20</span>));
System.out.println(sum(<span class="hljs-number">10</span>, <span class="hljs-number">20</span>, <span class="hljs-number">30</span>));
System.out.println(sum(<span class="hljs-number">10</span>, <span class="hljs-number">20</span>, <span class="hljs-number">30</span>, <span class="hljs-number">40</span>));
}
<span class="hljs-comment">// 一个方法有多个参数,包含可变参数,一般可变参数放在最后,前面的有几个就对应几个</span>
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-type">int</span> <span class="hljs-title function_">sum</span><span class="hljs-params">(<span class="hljs-type">int</span> b, <span class="hljs-type">int</span>... a)</span> {
<span class="hljs-type">int</span> <span class="hljs-variable">sum</span> <span class="hljs-operator">=</span> <span class="hljs-number">0</span>;
<span class="hljs-keyword">for</span> (<span class="hljs-type">int</span> i : a) {
sum += i;
}
<span class="hljs-keyword">return</span> sum;
}
}
</code></div></pre>
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