[OCAJP]變數的範圍

Given:

public class Whizlabs{
    public static void main(String[] args){
        int sum = 0;
        
        for (int x = 0; x <= 10; x++)
            sum += x;
        System.out.print("Sum for 0 to" + x);
        System.out.print(" = " + sum);
    }
}

Which is true?

A.

B.

C. Compilation fails due to error on line 6.
D. Compilation fails due to error on line 7.
E. An Exception is thrown at the runtime.

題解

程式第7行使用到第5行for迴圈內宣告的x變數，由於x變數只在for迴圈內才可以被有效地存取，而程式第7行已經在for迴圈之外，因此會發生編譯錯誤。