答案2.5。inta=7;floatx=2.5,y=4.7;x+a%3*(int)(x+y)%2/4;分步运算:a%3得1(x+y)得(7.2)(int)(7.2)得7于是a%3*(int)(x+y)成1*7得77%2得11/4做整除运算,得0x+0化为2.5+0.0得2.5浮点数。