Not sure what are the mistakes

[y19177]

New to C++ here. I'm trying to write a program to determine the shape of a triangle(practicing enum).
The program runs fine and it works as intended, but I got 3 mistakes notifications on the directory list (using VS code). Also, I have two underline ~ in my code, which indicates mistakes. I have included them by adding ~ in my code. Please help and point out my mistakes(one at the last line of main, the other at the end of the code). Thanks in advance.

#include <iostream>
#include <string>
enum tri {scalene, isosceles, equilateral,noTriangle}; 
tri id (int a, int b, int c);
void order(int &a, int &b);
std::string readTri (tri ABC); 
int main ()
{
    int a, b, c; 
    std::cout << " Enter the length of sides of an triangle: " << "\n";

    std::cout << " Enter the first side: " << "\n";  

    std::cin >> a;

    std::cout << " Enter the second side: " << "\n";  

    std::cin  >> b;

    std::cout << " Enter the third side: " << "\n";  

    std::cin >> c;

    order(b,c); 
    order(a,b);
    tri ABC = id(a,b,c); 
    std::cout << " This triangle is a/an " << readTri(ABC)  ~<<~ " triangle." << "\n"; 
    

}


void order(int &a, int &b)
{
   int x; 
   if (a > b)
   {
       x = a;
       a = b; 
       b = x; 
   }
    
}

tri id (int a, int b, int c)
{
    if( a + b < c)
    {
        return noTriangle; 
    }
    else if( a == b || a == c || b == c)
    {
        if(  a == b && b == c)
        {
            return isosceles;
        }
        return equilateral; 
    }
    else 
    {
        return scalene; 
    }
}


std::string readTri (tri ABC)
{
    std::string str; 
    switch(ABC)
    {
        case 0:
        {
            str = "scalene";
            break;
        }
        case 1: 
        {
            str = "isosceles";
            break;
        }
        case 2:
        {
            str = "equilateral"; 
            break;
        }
        case 3: 
        {
            str = "noTriangle"; 
            break; 
        }
    }
    return str; 
~}~

[keskiverto]

Online compiler merely warns about line 35:

 In function 'void order(int&, int&)':
35:8: warning: variable 'x' set but not used [-Wunused-but-set-variable]

Why do you have a variable that you don't use?

Oh, you have logical error on lines 38-40.
The a = b; b = a; does same as a = b;

[y19177]

Thanks for pointing out a typo, I meant to put a, b in increasing order.

[seeplus]

There is an error with order() - b = a??

For the switch, use the enum name rather than the number. In VS2019 this compiles with no warnings and with only a ~~ for the ABC definition as tri is an unscoped enum. Also, there is a problem with id as for 3 3 3 it's saying it's an isosceles!

#include <iostream>
#include <string>

enum tri { scalene, isosceles, equilateral, noTriangle };

tri id(int a, int b, int c);
void order(int& a, int& b);
std::string readTri(tri ABC);

int main()
{
	int a {}, b {}, c {};
	std::cout << " Enter the length of sides of an triangle:\n";

	std::cout << " Enter the first side: ";
	std::cin >> a;

	std::cout << " Enter the second side: ";
	std::cin >> b;

	std::cout << " Enter the third side: ";
	std::cin >> c;

	order(b, c);
	order(a, b);

	const tri ABC {id(a, b, c)};

	std::cout << " This triangle is a/an " << readTri(ABC) << " triangle.\n";
}

void order(int& a, int& b)
{
	if (a > b) {
		const int x {a};

		a = b;
		b = x;
	}
}

tri id(int a, int b, int c)
{
	if (a + b < c)
		return noTriangle;

	if (a == b || a == c || b == c) {
		if (a == b && b == c)
			return equilateral;

		return isosceles;
	}

	return scalene;
}

std::string readTri(tri ABC)
{
	std::string str;

	switch (ABC) {
		case scalene:
			str = "scalene";
			break;

		case isosceles:
			str = "isosceles";
			break;

		case equilateral:
			str = "equilateral";
			break;

		case noTriangle:
			str = "noTriangle";
			break;
	}

	return str;
}

order() could use std::swap()

void order(int& a, int& b)
{
	if (a > b)
		std::swap(a, b);
}

[y19177]

Thanks seeplus for suggestions on order(). I'm not sure why unscoped enum would cause any problem. Can you further explain? Also, what is the advantage of using const in

order(int &a,  int &b)
const tri ABC{id(a,b,c)}

Greatly appreciated. I'm learning.

[seeplus]

unscoped enum doesn't cause a problem by itself. It's a C++ guideline that enums should be scoped - ie given a name.

Basically, when something shouldn't change then define it as const so that if it is chnaged then the compiler will report an error.