C语言学习第四章T7

题目：输入三个数，判断这三个数对应长度的线段构成的三角形是什么类型。设计数据并测试程序。

主要代码：

# include <stdio.h>
int maxiumn (int x,int y,int z);
int main (void)
{
    int a,b,c;
    printf("triangle's a line:");
    scanf("%d",&a);
    printf("triangle's b line:");
    scanf("%d",&b);
    printf("triangle's c line:");
    scanf("%d",&c);
                                                //input tri's 3 line
    if (a<0 || b<0 || c<0)
    {
        printf("error!It's not a triangle!");
    }
    else
    {
        if (a+b<c || a+c<b || b+c<a)			//judge if it's tri or not
        {
            printf("error! \n");
        }
        else
        {
            int mac,l1,l2;
            mac=maxiumn(a,b,c);
            if (mac==a)							//judge the line from big to small
            {
                l1=b;
                l2=c;
            }
            else if (mac==b)
            {
                l1=a;
                l2=c;
            }
            else
            {
                l1=a;
                l2=b;
            }
            if (l1*l1+l2*l2==mac*mac)			//judge the shape of triangle
            {
                printf("it's a RT triangle \n");
            }
            else if (l1*l1+l2*l2<mac*mac)
            {
                printf("it's a acute angle triangle\n");
            }
            else
            {
                printf("it's an obtuse angle triangle\n");
            }
        }
    }
    return 0;
}

int maxiumn (int x,int y,int z)				//count the longest line
{
    int max;
    if (x>y)
    {
        max=x;
    }
    else
    {
        max=y;
    }
    if (max<z)
    {
        max=z;
    }
    printf("the max line:%d \n",max);
    return max;
}

运行结果：