double a,b,c; scanf(“%lf %lf %lf”,&a,&b,&c); if(a+b>c&&a+c>b&&c+b>a) printf(“Perimetro = %.1lf”,a+b+c); else printf(“Area = %.1lf”,(a+b)*c/2);
//注意两边之和大于第三边，是相应的条件
