Question

我不知道输出是什么意思？有人会帮我这个吗？请解释一下它是如何工作的。

  public class LastIndexOfExample{  
  public static void main(String args[]){  
   String s1="hello";  
   String s2="hello";  
   String s3="meklo";  
   String s4="hemlo";  
   System.out.println(s1.compareTo(s2));  
   System.out.println(s1.compareTo(s3));  
   System.out.println(s1.compareTo(s4));  
  }
}

然后输出是： 0 -5 -1

Answer 1

来自compareTo javadoc：

如果存在两个字符串不同的索引，则结果为两个字符在最低指数
之间的差异

完整的Javadoc：

    /**
     * Compares this string to the given string.
     *
     * <p>The strings are compared one {@code char} at a time.
     * In the discussion of the return value below, note that {@code char} does not
     * mean code point, though this should only be visible for surrogate pairs.
     *
     * <p>If there is an index at which the two strings differ, the result is
     * the difference between the two {@code char}s at the lowest such index.
     * If not, but the lengths of the strings differ, the result is the difference
     * between the two strings' lengths.
     * If the strings are the same length and every {@code char} is the same, the result is 0.
     *
     * @throws NullPointerException
     *             if {@code string} is {@code null}.
     */
    public native int compareTo(String string);

从在线文档（上面的链接）：

如果此String对象，则结果为负整数按字典顺序排列在参数字符串
之前

什么是java String compareTo方法和什么是Java词典

1 个答案: