单选题：若a、b、c1、c2、x、y均为整型变量，正确的switch 语句是（）。

若a、b、c1、c2、x、y均为整型变量，正确的switch 语句是（）。

@[D](2)

A. switch (a+b);
{ case 1: y=a+b; break;
case 0: y=a-b;
break;
}
B. switch a

{ case c1: y=a-b; break;

case c2: x=a*d; break;

default: x=a+b;

}
C. switch (a*a+b*b)
{ case 3:
case 1: y=a+b; break;
case 3: y=b-a; break;
}

D. switch(a-b)

{ default: y=a*b; break;

case 3: x=a+b; break;

case 10: case 11: y=a-b; break;

}




A.switch (a+b);
{ case 1: y=a+b; break;
case 0: y=a-b;
break;
}
B.switch a

{ case c1: y=a-b; break;

case c2: x=a*d; break;

default: x=a+b;

}
C.switch (a*a+b*b)
{ case 3:
case 1: y=a+b; break;
case 3: y=b-a; break;
}

D.switch(a-b)

{ default: y=a*b; break;

case 3: x=a+b; break;

case 10: case 11: y=a-b; break;

}



答案：D