3-5 三角形判断

//三角形判断#include<stdio.h>#include<math.h>int main(int argc,char const *argv[]){double x1,y1,x2,y2,x3,y3;printf("请输入三个点的坐标:\n");printf("x1=");scanf("%lf",&x1);printf("y1=");scanf("%lf",&y1);printf("x2=");scanf("%lf",&x2);printf("y2=");scanf("%lf",&y2);printf("x3=");scanf("%lf",&x3);printf("y3=");scanf("%lf",&y3);double a,b,c;double s=0,circumference=0,area=0;a=sqrt(pow(x1-x2,2)+pow(y1-y2,2));b=sqrt(pow(x1-x3,2)+pow(y1-y3,2));c=sqrt(pow(x2-x3,2)+pow(y2-y3,2));if(a+b>c&&a+c>b&&b+c>a){s=(a+b+c)/2;circumference=a+b+c;area=sqrt(s*(s-a)*(s-b)*(s-c));printf("周长：%.2f\n",circumference);printf("面积：%.2f\n",area);}else{printf("Impossible");}return 0;}