# include <stdio.h>
# include <math.h>
 main(void)
{
  float s1, s2, x1, x2;
  int n1, n2;
  long float sc, t, t1, t2;
 
  n1 = n2 = 10;
  printf("请输入s1和ns2：\n");
  scanf("%f %f", &s1, &s2);
  printf("请输入x1和x2：\n");
  scanf("%f %f", &x1, &x2);
  
  sc = ((n1-1)*s1*s1 + (n2-1)*s2*s2)/(n1 + n2 -2);
  t1 =sc * sc * (1/n1 + 1/n2);
  t2 = sqrt(t1);
  t = (x1 - x2)/t1;

  printf("sc = %lf, t1 = %lf, t2 = %lf, t = %lf", sc, t1, t2, t);

  return 0;
}
t1和t2输出为0，t输出为垃圾值？请教各位大虾，哪里存在问题？