没什么好说的,只要注意要是个三角形才能继续判断等腰和等边,比如1 1 2这种,要是先判断等边和等腰会把它识别成等腰

#include <iostream>
using namespace std;

int main() {
    int a, b, c;
    while (cin >> a >> b >> c) {
        if(a+b>c&&a-b<c)
            if(a==b&&b==c)cout<<"Equilateral triangle!\n";
            else if(a==b||b==c||a==c)cout<<"Isosceles triangle!\n";
            else cout<<"Ordinary triangle!\n";
        else cout<<"Not a triangle!\n";
    }return 0;
}