C :

#include<stdio.h>

int main()
{
	double A,B,C,T;
	scanf("%lf %lf %lf",&A,&B,&C);

	if(A+B>C&&A+C>B&&B+C>A)
	{
		T=A+B+C;
	    printf("Perimetro = %.1lf",T);
	}
	else
	{
	    T=(A+B)*C*0.5;
		printf("Area = %.1lf",T);
	}

    return 0;
}

C++ :

#include<cstdio>

using namespace std;

int main()
{
    double a,b,c;
    
    scanf("%lf %lf %lf",&a,&b,&c);

    if(a+b>c&&a+c>b&&b+c>a) 

    printf("Perimetro = %.1lf",a+b+c);
    
    else
    printf("Area = %.1lf",(a+b)*c*1/2.0);

    return 0;
}