Given:
public class Calculator { | |
public static void main(String[] args) { | |
int num = 5; | |
int sum; | |
do { | |
sum += num; | |
} while ((num--) > 1); | |
System.out.println("The sum is " + sum + "."); | |
} | |
} |
What is the result?
A.
The sum is 2
B.
The sum is 14
C.
The sum is 15
D. The loop executes infinite times
E. Compilation fails
題解
第4行宣告了一個sum整數變數,但沒有初始化。第7行的「sum += num;」可以拆解成:
sum = sum + num; |
由於sum變數並未初始化就要被取值作加法運算,因此會發生編譯錯誤。