c++,关于loop的问题，刚学一个月。大神帮帮忙！谢谢

[luciferp123]

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <math.h>
int main(void)
{

int i,X,Y;
float x,y;
float D;
X=3;
Y=6; /*centroid(3,6)*/
for(i=0;i<10;++i){
printf("Enter way point %d (x%d y%d):\n",i,i,i);

scanf("%f%f",&x,&y);

printf("*** Distance of way point %d from centroid = %.6f\n",i,D);

D=(double)sqrt((x-X)*(x-X)+(y-Y)*(y-Y));


}

return 0;
}
下面是题目需要的display
Enter way point 1 (x1 y1): 3 4
*** Distance of way point 1 from centroid = 5.830952
*** Total distance travelled = 0.000000
Enter way point 2 (x2 y2): 1 2
*** Distance of way point 2 from centroid = 3.162278
*** Total distance travelled = 2.828427
Enter way point 3 (x3 y3): -2 1.1
*** Distance of way point 3 from centroid = 0.100000
*** Total distance travelled = 5.960519
Enter way point 4 (x4 y4): -5 -6
*** Distance of way point 4 from centroid = 7.615773
*** Total distance travelled = 13.668307
Enter way point 5 (x5 y5): -2 1.000001
*** Distance of way point 5 from centroid = 0.000001
*** Total distance travelled = 21.284081

想问怎么才能算出Total distance travelled，用后来input的数值减去之前输入的数值
Total distance travelled=(double)sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
code 怎么写？
而且loop 会在*** Distance of way point 5 from centroid = 0.000001停止要求输入新的x，y坐标，code是怎么写的？
感谢。

[ipqtjmqj]

当然是建个三个变量保存上次的坐标，以及累计的距离

[赵4老师]

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <math.h>
int main(void)
{

    int i,X,Y;
    double x,y,x1,y1;
    double D,TD=0.0;
    X=3;
    Y=6; /*centroid(3,6)*/
    for (i=0;i<10;++i) {
        printf("Enter way point %d (x%d y%d):\n",i,i,i);
        scanf("%lf%lf",&x,&y);
        D=sqrt((x-X)*(x-X)+(y-Y)*(y-Y));
        printf("*** Distance of way point %d from centroid = %.6lf\n",i,D);
        if (i==0) {
            D=0.0;
        } else {
            D=sqrt((x-x1)*(x-x1)+(y-y1)*(y-y1));
        }
        TD+=D;
        printf("*** Total distance travelled = %.6lf\n",D);
        x1=x;
        y1=y;
    }
    return 0;
}

[赵4老师]

上帖代码23行 printf("*** Total distance travelled = %.6lf\n",D); 纠正为 printf("*** Total distance travelled = %.6lf\n",TD);