π比较标准写法 #include <iostream>#include <math.h>using namespace std;const double pi=acos(-1);int main(){ double r; cin>>r; printf("%.4f ",2*r); printf("%.4f ",pi*r*2); printf("%.4f 随笔 2023-11-01 214 点赞 3 评论 324 浏览
