为什么报错？？？？？？？

using namespace std;
string n(int a,int b,int c)
{
	if(z(a,b,c)!="Right triangle" && r(a,b,c)!="Acute triangle" && d(a,b,c)!="Obtuse triangle" && y(a,b,c)!="Isosceles triangle" && p(a,b,c)!="Equilateral triangle")
	{
		return "Not triangle";
	}
}
string z(int a,int b,int c)
{
	int t=min(a,b,c);
	int k=max(a,b,c);
	if(t==a)
	{
		int y=min(b,c);
	}
	if(t==b)
	{
		int y=min(a,c);
	}
	if(t==c)
	{
		int y=min(a,b);
	}
	if(sqrt(t)+sqrt(y)==sqrt(k))
	{
		return "Right triangle";
	}
}
string r(int a,int b,int c)
{
	int t=min(a,b,c);
	int k=max(a,b,c);
	if(t==a)
	{
		int y=min(b,c);
	}
	if(t==b)
	{
		int y=min(a,c);
	}
	if(t==c)
	{
		int y=min(a,b);
	}
	if(sqrt(t)+sqrt(y)>sqrt(k))
	{
		return "Acute triangle";
	}
}
string d(int a,int b,int c)
{
	int t=min(a,b,c);
	int k=max(a,b,c);
	if(t==a)
	{
		int y=min(b,c);
	}
	if(t==b)
	{
		int y=min(a,c);
	}
	if(t==c)
	{
		int y=min(a,b);
	}
	if(sqrt(t)+sqrt(y)<sqrt(k))
	{
		return "Obtuse triangle";
	}
}
string y(int a,int b,int c)
{
	if(a==b || a==c || b==c)
	{
		return "Isosceles triangle";
	}
}
string p(int a,int b,int c)
{
	if(a==b && b==c && a==c)
	{
		return "Equilateral triangle";
	}
}
int main()
{
    int a,b,c;
    cin >> a >> b >> c;
    cout << n(a,b,c) << endl;
    cout << z(a,b,c) << endl;
    cout << r(a,b,c) << endl;
    cout << d(a,b,c) << endl;
    cout << y(a,b,c) << endl;
    cout << p(a,b,c) << endl;
    return 0;
}