三角形

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <stdio.h>//header standard Input/ouput
#include<stdbool.h>
#include<assert.h>
#include<math.h>


int main()
{
	int a, b, c,temp;
	scanf("%d%d%d", &a, &b,&c);
	int num[3] = { a,b,c };
	for (int j = 0;j < 3;j++) {
		for (int i = 2;i >= 0;i--) {
			if (num[i] < num[i - 1]) {
				temp = num[i];
				num[i] = num[i - 1];
				num[i - 1] = temp;
			}
		}
	}

	int short1 = num[0] * num[0], short2 = num[1] * num[1];
	int long1 = num[2] * num[2];

	if (num[0] + num[1] <= num[2]) {
		printf("%s", "not a triangle");
	}
	else if (num[0]==num[1] && num[1] == num[2] && num[0]==num[2]) {
		printf("%s", "regular triangle");
	}
	else {
		if (short1 + short2 == long1) {
			printf("%s", "rectangular triangle");
		}
		else if (short1 + short2 > long1) {
			if (num[0] == num[1] || num[1] == num[2]) {
				printf("%s", "isosceles acute triangle");
			}
			else {
				printf("%s", "acute triangle");
			}
		}
		else if (short1 + short2 < long1) {
			if (num[0] == num[1] || num[1] == num[2]) {
				printf("%s", "isosceles obtuse triangle");
			}
			else {
				printf("%s", "obtuse triangle");
			}
		}
	}
}