阅读下面的程序: class StringDemo{ public static void main(String[]args){ String s1=“a"; String s2=“b"; show(s1,s2); System.out.printIns1+s2); public static void show(String s1,String s2){ s1=s1+”q”; s2=s2+s1; 上述程序的运行结果为() A、ab B、aqb C.agbaq D.aqaqb

该程序有语法错误，正确的程序如下：

class StringDemo {
    public static void main(String[] args) {
        String s1 = "a";
        String s2 = "b";
        show(s1, s2);
        System.out.println(s1 + s2);
    }

    public static void show(String s1, String s2) {
        s1 = s1 + "q";
        s2 = s2 + s1;
        System.out.println(s2);
    }
}

运行结果为 C、agbaq。

相关问题

public class Test{ public static void main(String[] args){ String s1 = "runoob"; String s2 = "runoob"; System.out.println("s1 == s2 is:" + s1 == s2);}}

The code you provided has a small mistake in the print statement. The expression `"s1 == s2 is:" + s1` is concatenated with `== s2` before being passed to `System.out.println()`. This causes a compilation error because you cannot concatenate a string with a boolean value directly.

To fix this, you need to use parentheses to group the concatenation expression properly. Here's the corrected code:

public class Test {
    public static void main(String[] args) {
        String s1 = "runoob";
        String s2 = "runoob";
        System.out.println("s1 == s2 is: " + (s1 == s2));
    }
}

In this corrected code, the expression `(s1 == s2)` is properly grouped and then concatenated with the string `"s1 == s2 is: "`.

下面程序的运行结果是（） ‍ ‌public class Example { public static void main(String[] args) { String s1 = new String("Hello"); String s2 = new String("Hello"); System.out.print(s1 == s2); String s3 = "Hello"; String s4 = "Hello"; System.out.print(s3 == s4); s1 = s3; s2 = s4; System.out.print(s1 == s2); } }

程序的运行结果是falsefalsetrue。

原因是：在Java中，用new关键字创建的字符串对象，每次都会在堆内存中新分配一块内存，因此s1和s2指向的是不同的对象，所以s1==s2的结果为false。

而用双引号创建的字符串对象，会首先在常量池中查找是否已有相同值的对象，如果有，则直接返回该对象的引用，如果没有，则创建一个新的字符串对象并存储在常量池中。因此s3和s4指向的是同一个对象，所以s3==s4的结果为true。

最后s1=s3，s2=s4，因此s1和s2也指向同一个对象，所以s1==s2的结果为true。