习题1-5，距离

输入4个浮点数x₁,y₁,x₂,y₂，输出平面坐标系中点(x₁，y₁)到点(x₂，y₂)的距离。

#include <cstdlib>
#include <iostream>
#include <math.h>
using namespace std;


int main(int argc, char *argv[])
{
    int x1,x2,y1,y2;
    scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
    printf("%.4f",sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)));
    system("pause");
    return EXIT_SUCCESS;
}