最近有点尿频女:关于指针大家来看看

程序如下,最近点计算,程序记数单位正方形内随机生成的点对.
/* 点数据类型接口 point.h */

/*include <math.h>

typedef struct point {
float x; float y;
}point;
float distance(point a, point b)
{
float dx = a.x - b.x, dy = a.y - b.y;
return sqrt(dx*dx + dy*dy);
}
*/
#include <stdio.h>
#include <stdlib.h>
#include "point.h"
float randFloat()
{
return 1.0 * rand() / RAND_MAX;
}

int main(int argc, char *argv[])
{
float d = atof(argv[2]);
int i, j, cnt = 0, N = atoi(argv[1]);
point *a = malloc(N*sizeof(point));
//问题就在这,改成 point *a = malloc(N*sizeof(point*));
// 运行结果一样,为什么??这样声明a是什么?原来那样声明又是什么?
printf("%d", sizeof(point));
printf("%d", sizeof(point*));

for(i = 0; i < N; i++)
{
a[i].x = randFloat();
a[i].y = randFloat();
}
for(i = 0; i < N; i++)
for(j = i+1; j < N; j++)
if(distance(a[i], a[j]) < d) cnt++;
printf("%d edges shorter than %f\n", cnt, d);

system("pause");
return 0;
}