實訓JAVA語言設計——程式查錯

 查錯：11  

1.                               public class WhatHappens {

2.                               public static void main(String[] args) {

3.                                   StringBuffer[] stringBuffers = new StringBuffer[10];

4.                                    for (int i = 0; i < stringBuffers.length; i ++) {

5.                                       stringBuffers[i].append("StringBuffer at index " + i);

6.                                   }

7.                               }

8.                           }

  Answer:程式在第定義了數組StringBuffers[]，但在使用數組StringBuffers對象時沒有初始化，要初始化後才能使用。如下第5行為對數組對象初始化

1.                           public class ThisHappens {

2.                               public static void main(String[] args) {

3.                                   StringBuffer[] stringBuffers = new StringBuffer[10];

4.                                        for (int i = 0; i < stringBuffers.length; i ++) {

5.                                        stringBuffers[i] = new StringBuffer();

6.                                       stringBuffers[i].append("StringBuffer at index " + i);

7.                                   }

8.                               }

9.                           }