问个问题：怎样在不是三角形的时候，不输出面积，直接输出not

#include<stdio.h>#include<math.h>int main(void){float a,b,c,t,p,area;scanf("%f,%f,%f",&a,&b,&c);if(a<b){t=a;a=b;b=t;}if(a<c){t=a;a=c;c=t;}if(b<c){t=b;b=c;c=t;}if((a<(b+c))&&(b>(a-c))) p=(a+b+c)/2; area=sqrt(p*(p-a)*(p-b)*(p-c)); printf("area=%.3f\n",area);if((a==b)&&(b==c)) printf("equilateral triangle"); else if((a*a==b*b+c*c)&&((a==b)||(b==c)||(a==c))) printf("isosceles right triangle"); else if((a*a==b*b+c*c)&&((a!=b)&&(b!=c)&&(a!=c))) printf("right triangle"); if((a*a!=b*b+c*c)&&((a!=b)&&(b!=c)&&(a!=c))&&(a<(b+c))&&(b>(a-c))) printf("triangle");if((a>=(b+c))||(b<=(a-c))) printf("Not triangle");return 0; }

好难

先判断任意两边之和大于第三边