大佬们，搞了好久没出来，刚学函数，求助

代码如下：

#include<bits/stdc++.h>
using namespace std;
double dis(double x1, double y1,double x2,double y2){
	double a;
	a=sqrt(abs((x2-x1))*abs((x2-x1))+abs((y2-y1))*abs((y2-y1)));
	return a;
}
int main (){
	int x1,y1,x2,y2,x3,y3;
	cin>>x1>>y1>>x2>>y2>>x3>>y3;
	double c;
	int dis1=dis(x1,y1,x2,y2);
	int dis2=dis(x2,y2,x3,y3);
	int dis3=dis(x1,y1,x3,y3);
	c=dis1+dis2+dis3;
	printf("%.2lf",c);
	return 0;
} ```