两点间距离(C++)

题解：

#include <cstdio>
#include <iostream>
#include <cmath>
using namespace std;

int main() 
{
    double a, b, c, d;
    double distance;
    cin >> a >> b >> c >> d;
    distance = sqrt(((c-a)*(c-a)) + ((d-b)*(d-b)));
    printf("%.4lf",distance);
    return 0;
}