两点之间距离 结构体 函数

#include <stdio.h>
#include <stdlib.h>
struct point
{
double x;
double y;
}point;

double s(struct point m,struct point n)
{
double o;
o=sqrt((m.x-n.x)(m.x-n.x)+(m.y-n.y)(m.y-n.y));
return o;
}
int main()
{
struct point m;
struct point n;
scanf("%lf %lf %lf %lf",&m.x,&m.y,&n.x,&n.y);
printf("%.2lf",s(m,n));
}