算法：从键盘输入能够构成三角形的三条边长，编程计算该三角形的面积

#include "stdio.h"
#include "math.h"

int main(void)
{
float a = 0, b = 0, c = 0, p = 0;
float area = 0;

printf("Please input three sides of triangle:");
scanf_s("%f %f %f", &a, &b, &c);

if((a + b) > c && (a + c) > b && (b + c) > a)
{
p = (a + b + c) / 2;
area = sqrt(p * (p - a) * (p - b) * (p - c));
}
else
printf("Triangle does not exist！\n");

printf("The area of triangle is:%f\n", area);

return 0;
}

#include "stdio.h"
#include "math.h"

int main(void)
{
float a = 0, b = 0, c = 0;
float p = 0;

printf("Please input three sides of triangle:");
scanf_s("%f %f %f", &a, &b, &c);

switch (a + b > c  &&  a + c > b && b + c > a)
{
case 0:printf("Triangle does not exist！\n"); break;
case 1:
p = (a + b + c)*0.5;
printf("The area of triangle is:%f\n", sqrt(p * (p - a) * (p - b) * (p - c)));
break;
}

return 0;
}