小白日记8

include<stdio.h>

include<math.h>//刚开始写的时候没有带这个math库一直报错

int main(){
double xa,ya,xb,yb,l;
scanf("%lf %lf",&xa,&ya);
scanf("%lf %lf",&xb,&yb);
l=sqrt((xa-xb)(xa-xb)+(ya-yb)(ya-yb));//会用了sqrt
printf("%.3lf",l);
return 0;
}