#include<stdio.h>
main()
{
  char sex,sports,diet;
  float myheight,maheight,faheight;
  printf("are you a boy(b) or a girl(g)?");
  scanf("%c",&sex);
  printf("please input your mather'height--(cm):");
  scanf("%f",&maheight);
  printf("please input your father'height--(cm):");
  scanf("%f",&faheight);

  printf("do you like sports(y/n)?");
  getchar();
  scanf("%c",&sports);
  printf("do you have a good habit of diet(y/n)?");
   getchar();
  scanf("%c",&diet);
  if(sex=='b')
   myheight=(maheight+faheight)*0.54;
   else
   myheight=(maheight+faheight)*0.5;
  if(sports=='y')
   myheight=myheight*1.102;
   else
   myheight=(faheight*0.923+maheight)*0.5;
   if(diet=='y')
   myheight=myheight*1.1015;
  printf("your future height will be  %f (cm)\n",myheight);
  getch();
   
}
程序中的getchar为什么不可省略，getchar的详细用法及注意事项，请详细讲一下
谢谢