单击命令按钮时,下列程度段的执行结果为( )。 Pfivate Sub Command1_Click() Dima As Integer,b As Integer, c As Integer a=2:b=4:c=6 Call S1(a,B) Print 'a=';a;'b=';b;'c=';c Call S2(a,B) Print 'a=';a;'b=';b;'c=';c; End Sub Private Sub S1(x As Integer, y As Integer) Dim c As Integer x=2*x:y=y+2:c=x+y End Sub Sub S2(x As Integer, By Val y As Integer) Dim e As Integer x=2*x:y=y+2:e=x+y End Sub
A.a=4 b=6 c=6 a=4 b=6 c=6
B.a=8 b=6 c=6 a=8 b=6 c=6
C.a=4 b=6 c=6 a=8 b=6 c=6
D.a=8 b=6 c=6 a=4 b=6 c=6
A.a=4
B.a=8
C.a=4
D.a=8
【参考答案】
C
解析:在定义子过程的参数时,如果在参数前加上ByVal,表示是“传值”参数,主调函数中参数的值不被改变,否则表示是“传地址”参数,参数值会被调用的子过程改变。