C语言学习10

判断三角形的类型

根据输入的三角形的三条边判断三角形的类型，并输出它的面积。

 #include <stdio.h>
 #include <math.h>

 void judge_1(double x, double y, double z);

 void main()
 {
     double a, b, c;
     printf("输入三边 a b c: ");
     scanf("%lf %lf %lf", &a, &b, &c);
     judge_1(a, b, c);
     printf("\n");
 }

 void judge_1(double x, double y, double z)
 {
     double m, s, area;
     if(x>y)
     {
         m = y;
         y = x;
         x = m;
     }
     if(x>z)
     {
         m = z;
         z = x;
         x = m;
     }
     if(y>z)
     {
         m = z;
         z = y;
         y = m;
     }

     if(x+y>z && z-y<x)
     {
         s = (x+y+z)/2.0;
         area = sqrt(s*(s-x)*(s-y)*(s-z));
         if(x == y && x== z)
         {
             printf("等边三角形-面积为:%lf\n", area);
         }
         else if(x == y || y == z || x==z)
         {
             printf("等腰三角形-面积为:%lf\n", area);
         }
         else if(x*x + y*y == z*z)
         {
             printf("直角三角形-面积为:%lf\n", area);
         }
         else
         {
             printf("普通三角形-面积为:%lf\n", area);
         }
     }
     else
     {
         printf("不能构成三角形\n");
     }
 }