switch case 语句判断一个变量与一系列值中某个值是否相等，每个值称为一个分支。
switch - 语法
switch(expression) { case value : //Statements break; //可选case value : //Statements break; //可选
//您可以有任意数量的 case 语句。 default : //Optional //Statements }
switch - 流程图
switch -示例
public class Test {
public static void main(String args[]) {
//char grade=args[0].charAt(0);
char grade=C;
</span><span class="kwd">switch</span><span class="pun">(</span><span class="pln">grade</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
</span><span class="kwd">case</span><span class="pln"> </span><span class="str">A</span><span class="pln"> </span><span class="pun">:</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Excellent!"</span><span class="pun">);</span><span class="pln">
</span><span class="kwd">break</span><span class="pun">;</span><span class="pln">
</span><span class="kwd">case</span><span class="pln"> </span><span class="str">B</span><span class="pln"> </span><span class="pun">:</span><span class="pln">
</span><span class="kwd">case</span><span class="pln"> </span><span class="str">C</span><span class="pln"> </span><span class="pun">:</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Well done"</span><span class="pun">);</span><span class="pln">
</span><span class="kwd">break</span><span class="pun">;</span><span class="pln">
</span><span class="kwd">case</span><span class="pln"> </span><span class="str">D</span><span class="pln"> </span><span class="pun">:</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"You passed"</span><span class="pun">);</span><span class="pln">
</span><span class="kwd">case</span><span class="pln"> </span><span class="str">F</span><span class="pln"> </span><span class="pun">:</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Better try again"</span><span class="pun">);</span><span class="pln">
</span><span class="kwd">break</span><span class="pun">;</span><span class="pln">
</span><span class="kwd">default</span><span class="pln"> </span><span class="pun">:</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Invalid grade"</span><span class="pun">);</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Your grade is "</span><span class="pln"> </span><span class="pun">+</span><span class="pln"> grade</span><span class="pun">);</span><span class="pln">
}
}
使用各种命令行参数编译并运行上述程序。这将产生以下输出-
Well done Your grade is C
