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("
");
}

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
", area);
        }
        else if(x == y || y == z || x==z)
        {
            printf("等腰三角形-面积为:%lf
", area);
        }
        else if(x*x + y*y == z*z)
        {
            printf("直角三角形-面积为:%lf
", area);
        }
        else
        {
            printf("普通三角形-面积为:%lf
", area);
        }
    }
    else
    {
        printf("不能构成三角形
");
    }
}