求教大佬

#include<stdio.h>
#include<math.h>
double dis(double x,double y,double u,double v);
int main(void){
    double x[3],y[3];
    double l;
    for(int i=0;i<3;i++){
        scanf("%lf%lf",&x[i],&y[i]);
    }
    l=dis(x[0],y[0],x[1],y[1])+dis(x[0],y[0],x[2],y[2])+dis(x[1],y[1],x[2],y[2]);
    printf("%.2lf",l);
    
    return 0;
}
double dis(double x,double y,double u,double v){
    int ans=sqrt(pow(x-u,2)+pow(y-v,2));
    return ans;
}