c++ - 如何用C语言计算两点之间距离（超大数据）？

Question

//计算x y之间距离
double distance(point a,point b){

return sqrt(    (a.x - b.x)*(a.x - b.x)  +   (a.y -b.y)*(a.y -b.y)  );

}

想要直接以这样的公式计算，但是当输入大于六位数会出错。需要输入小于等于1000000的数字。
所以有没有能够数据不溢出的解决方法。
当然计算结果只需要保留后两位即可。

参考代码：

#include <stdio.h>
#include <stdlib.h>
#include "math.h"
typedef struct point {
    double x;
    double y;
}point;
point array[30001];

double distance(point a,point b);
int main(int argc, char *argv[]) 
{
    while(1){


    int n,i,j,count;
    double maxdis,temp;
    scanf("%d",&n);
    for(i = 0;i<n;i++){
        scanf("%f %f",&array[i].x,&array[i].y);
        
    }
    for(i = 0;i<n;i++){
        //printf("%d %d\n",array[i].x,array[i].y);
        //printf("dis:%.2f\n",distance(array[0],array[i]));

    }
    maxdis = 0.0;
    for(i = 0;i<n;i++){
        for(j = i;j<n;j++){
            if(distance((array[i]),(array[j])) > maxdis ){
                //printf("maxdis = :%.2f\n",distance((array[i]),(array[j])));
                maxdis =distance((array[i]),(array[j]));
            }
        }
    }
    printf("%.2f",maxdis);
    
}
    
    
    system("pause");
    return 0;
}

//计算x y之间距离
double distance(point a,point b){
    return sqrt(    (a.x - b.x)*(a.x - b.x)  +   (a.y -b.y)*(a.y -b.y)  );
}

代码已经贴出。

Answer 1

Please post the definition of point...
To be honest, if it is only 1 million W, double is easy and stress-free. Could it be that int is used...?

Answer 2

I made the following modifications to your code:
Changed the scanf reading type from %f to %lf. The input data cannot be read using %f on my machine.
There is no problem compiling on my computer and the running results are normal.
The comment above has already solved this problem.

Answer 3

Use high precision directly for very large numbers. This has nothing to do with whether the distance is calculated

Answer 4

To tell you something unrelated to the problem... you can try using high precision.