Introduction - If you have any usage issues, please Google them yourself
#include<stdio.h>
#include<math.h>
main()
{
double a,b,c,p,S,i
printf("Input a,b,c\n")
scanf(" lf lf",&a,&b,&c)
if(a+b>c&&a+c>b&&b+c>a){
p=(a+b+c)/2
S=sqrt((p-a)*(p-b)*(p-c))
i=0
printf("S= lf\n",S)
if(a==b&&b==c){
printf("等边三角形\n")
i++
}
else if(a==b||a==c||b==c){
printf("等腰三角形\n")
i++
}
if(a*a+b*b==c*c||a*a+c*c==b*b||b*b+c*c==a*a){
if(i==1)
printf("等腰直角三角形\n")
else
printf("直角三角形\n")
i++
}
if(i==0)
printf("一般三角形\n")
}
else
printf("DATA ERROR!\n")
}