Linghaiya · 发布于 2025-11-16 · 浏览 298 回复 0

double r;
scanf("%lf", &r);
double diameter = 2 * r;
double circumference = diameter * 3.1415926;
double area = 3.1415926 * r * r;
printf("%.4f %.4f %.4f\n", diameter, circumference, area);
return 0;