19）若有定义语句 int a,b; double x; 则下列选项中没有错误的是 (A) switch (x%2) { case 0: a++; break; case 1: b++; break; default: a++; b++; } (B) switch ((int)x/2.0) { case 0: a++; break; case 1: b++; break; default : a++; b++; } (C) switch((int)x%2) { case 0: a++; break; case 1: b++; break; default : a++; b++; } (D)switch((int)(x)%2) { case 0.0: a++; break; case 1.0: b++; break; default : a++; b++; }