#include<stdio.h> #include<math.h> #define INF 1e-6 int main() { double a,b,c; int t; while(1) { printf("please input three edge of the Triangle/n"); scanf("%lf%lf%lf",&a,&b,&c); if(a<=0||b<=0||c<=0) { printf("error :edge length can't be negative/n"); } else if(fabs(a+b-c)<INF || fabs(a+c-b)<INF || fabs(b+c-a)<INF) { printf("error: not a Triangle/n"); } else if(fabs(a-b)<INF && fabs(b-c)<INF) { printf("Equilateral Triangle/n"); } else if(fabs(a-b)<INF || fabs(a-c)<INF || fabs(b-c)<INF) { printf("Isosceles Triangle /n"); } else { printf("normal Triangle/n"); } printf("input 1 to continue,input 0 to exit:/n"); scanf("%d",&t); if(t == 1) { continue; } else if(t == 0) { break; } } return 0; }