#include <stdio.h>
#include <math.h>
struct Triangle{
double a,b,c;
};
int main(void) {
struct Triangle t;
double p,s;
scanf("%lf %lf %lf",&t.
a,&t.
b,&t.
c); printf("a:%lf\nb:%lf\nc:%lf\n",t.
a,t.
b,t.
c); p=(t.a+t.b+t.c)/2.0;
s
=sqrt(p
*(p
-t.
a)*(p
-t.
b)*(p
-t.
c)); return 0;
}
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