找出平面上距离最近的两个点

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cmath>
#include <string>
#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
struct point
{
point(double x, double y)
{
x_ = x;
y_ = y;
}
double x_;
double y_;
};

int main(int argc, char* argv[])
{
int n;
scanf("%d", &n);

vector<point> pvec;
for(int i = 0; i < n; ++i)
{
double x;
double y;
scanf("%lf%lf", &x, &y);
point p(x, y);
pvec.push_back(p);
}

int mlen = 0;
int start = 0;
int end = 0;
for(int i = 0; i < pvec.size(); ++i)
{

for(int j = i + 1; j < pvec.size(); ++j)
{

double d2 = pow(pvec[i].x_ - pvec[j].x_, 2) + pow(pvec[i].y_ - pvec[j].y_, 2);

if(mlen == 0)
{
mlen = d2;
}else if(mlen > d2)
{
mlen = d2;
start = i;
end = j;
}else
{}

}

}

if(start < end)
{
printf("closest point: %d,%d\n", start, end);
}else
{
printf("closest point: %d,%d\n", end, start);
}

return 0;
}