Java 代码

import java.util.Scanner;

public class Main
{
    public static void main (String[] arg)
    {
        Scanner cin = new Scanner(System.in);

        double a = cin.nextDouble();
        double b = cin.nextDouble();
        double c = cin.nextDouble();

        if ( (a+b)> c && (b+c)>a && (c+a)>b)
            System.out.println("Perimetro = " + String.format("%.1f", a+b+c));
        else 
            System.out.println("Area = " + String.format("%.1f", (a+b)*c/2.0));
    }
}