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argument to the constructor Vector::Vector(int)

firix (438)
Hi Guys,

I define a type Vec4 as a vector of four floats.
I want to define a class Vector similar to Vec4 ,but with the size given as an argument to the constructor Vector::Vector(int)

How do I change Vec4?
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struct floatt{
float f[4];
floatt(float f1, float f2, float f3, float f4)
{
f[0] = f1;
f[1] = f2;
f[2] = f3;
f[3] = f4;
}

floatt(const floatt &r)
{
f[0] = r.f[0];
f[1] = r.f[1];
f[2] = r.f[2];
f[3] = r.f[3];
	}
floatt &operator=(const floatt &r)
{
f[0] = r.f[0];
f[1] = r.f[1];
f[2] = r.f[2];
f[3] = r.f[3];
return *this;
}

};



class Vec4{
	vector<floatt> fval;
public:
	Vec4()
	{
		fval.push_back(floatt(rand() % 2 + 2.1f, rand() % 3 + 1.7f,rand() % 5 + 7.3f, rand() % 3 + 4.9f));
	}

	Vec4(floatt f)
	{
		fval.push_back(floatt(f));
	}
	Vec4(const Vec4 &f)
	{
		fval = f.fval;
	}

	Vec4 &operator=(const Vec4 &f)
	{
		fval =  f.fval;
		return *this;
	}


	void display()const
	{
		cout << "("<< fval[0].f[0] << ")" << "(" << fval[0].f[1] << ")" <<  "(" <<fval[0].f[2] << ")"<<"("<<fval[0].f[3]<< ")" << endl;

	}

	Vec4 operator+(const Vec4 &v)const
	{
		Vec4 result = *this;
		result.fval[0].f[0] += v.fval[0].f[0];
		result.fval[0].f[1] += v.fval[0].f[1];
		result.fval[0].f[2] += v.fval[0].f[2];
		result.fval[0].f[3] += v.fval[0].f[3];
		
		return result;
	}

	Vec4 operator-(const Vec4 &v)const
	{
		Vec4 result = *this;
		result.fval[0].f[0] -= v.fval[0].f[0];
		result.fval[0].f[1] -= v.fval[0].f[1];
		result.fval[0].f[2] -= v.fval[0].f[2];
		result.fval[0].f[3] -= v.fval[0].f[3];
		
		return result;
	}

	Vec4 operator/(const Vec4 &v)const
	{
		Vec4 result = *this;
		result.fval[0].f[0] /= v.fval[0].f[0];
		result.fval[0].f[1] /= v.fval[0].f[2];
		result.fval[0].f[2] /= v.fval[0].f[3];
		result.fval[0].f[3] /= v.fval[0].f[4];
		
		return result;
	}

	Vec4 operator*(const Vec4 &v)const
	{
		Vec4 result = *this;
		result.fval[0].f[0] *= v.fval[0].f[0];
		result.fval[0].f[1] *= v.fval[0].f[1];
		result.fval[0].f[2] *= v.fval[0].f[2];
		result.fval[0].f[3] *= v.fval[0].f[3];
		
		return result;
	}

	
	Vec4 &operator+=(const Vec4 &v)
	{
		this->fval[0].f[0] += v.fval[0].f[0];
		this->fval[0].f[1] += v.fval[0].f[1];
		this->fval[0].f[2] += v.fval[0].f[2];
		this->fval[0].f[3] += v.fval[0].f[3];

		return *this;

	}
	Vec4 &operator-=(const Vec4 &v)
	{
		this->fval[0].f[0] -= v.fval[0].f[0];
		this->fval[0].f[1] -= v.fval[0].f[1];
		this->fval[0].f[2] -= v.fval[0].f[2];
		this->fval[0].f[3] -= v.fval[0].f[3];

		return *this;

	}
	Vec4 &operator*=(const Vec4 &v)
	{
		this->fval[0].f[0] *= v.fval[0].f[0];
		this->fval[0].f[1] *= v.fval[0].f[1];
		this->fval[0].f[2] *= v.fval[0].f[2];
		this->fval[0].f[3] *= v.fval[0].f[3];

		return *this;

	}
	Vec4 &operator/=(const Vec4 &v)
	{
		this->fval[0].f[0] /= v.fval[0].f[0];
		this->fval[0].f[1] /= v.fval[0].f[1];
		this->fval[0].f[2] /= v.fval[0].f[2];
		this->fval[0].f[3] /= v.fval[0].f[3];

		return *this;

	}


	float &operator [] (int index)	
	{ 	

		return  this->fval[0].f[index];
	
	}

	friend ostream &operator<<(ostream &os, Vec4 &v);
	friend istream &operator>>(istream &is, Vec4 &v);



};


ostream &operator<<(ostream &os, Vec4 &v)
{
	return  os << "(" << v.fval[0].f[0] << ")"  << "(" << v.fval[0].f[1] << "(" << v.fval[0].f[2] << ")" << "(" << v.fval[0].f[3] << ")" <<   endl;

}

istream &operator>>(istream &is, Vec4 &v)
{
	return is >>  v.fval[0].f[0] >> v.fval[0].f[1] >> v.fval[0].f[2] >> v.fval[0].f[3];
}
ne555 (10692)
There are several ways
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//using templates (vector<4> v;)
template<unsigned int n>
class vector{
private:
  float v[n];
};
//dynamical allocation
class vector{
private:
  float *v;
public:
  vector(unsigned int n){ v=new float[n]; }
//you will need to do the destructor and copy constructor too
};
//use std::vector
class vector{
private:
  std::vector<float> v;
  vector(unsigned int n){ v.resize(n); }
};

However you will need to modify all your functions (use loops)

Why are you always using f[0]? Just make one value instead of an array then.
firix (438)
how ?
ne555 (10692)
how what?
Using loops:
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Vector & operator+=(const Vector &v)const
	{
                for(int K=0; K<n; K++)
		    this->val[K] += v.val[K];
		return *this;
	}


Why an array?
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class Vec4{
	//vector<floatt> fval; //you never use anything besides the first cell
         floatt fval;
//...
};
Last edited on
firix (438)
class Vec4{
//vector<floatt> fval; //you never use anything besides the first cell
floatt fval;
//...
};



I could not understand it?
ne555 (10692)
I could not understand it?
Are you asking if you understand? (please, be more specific)

I suppose Vec4 is one vector of four components (coordinates, and weight maybe). in floatt you have already that information.

Only the first cell 
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result.fval[0].f[0] /= v.fval[0].f[0];
result.fval[0].f[1] /= v.fval[0].f[2];
result.fval[0].f[2] /= v.fval[0].f[3];
result.fval[0].f[3] /= v.fval[0].f[4];
firix (438)
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 struct floatt{
 float f[4];
};


Is it that correct ?
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 class Vec4{
 floatt fval;
};


Is it that correct ?

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 class Vec4{
vector<floatt> fval;
};

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