以下程序运行后的输出结果是
#include＜stdio.h＞
#define PT 3.5;
#define S(x) PT*x*x;
main()
int a=1, b=2; printf("%4.1f\n", S(a+b));

A) switch(x)
case 1.0: printf("*\n");
case 2.0: printf(" * * \n" );
B) switch((iht)x);
case 1: printf(" * \n" );
case 2: printf(" * * \n" );
C) switch(a +b)
case 1: printf(" * \n" );
case 2 + 1: printf(" * * \n" );
D) switch(a + b)
case 1: pfintf(" * \n" );
case c: pfintf(" * * \n");