A magic square is an array of numbers where the sum of each column or row return the same value. This class can analyze the array for a magic square.

magicsquare.cpp

class Square
{
private:
	const int size;
	int* grid;
public:
	Square() : size(4) {grid = new int[size * size];}
	Square(int size) : size(size) {grid = new int[size * size];}
	
	void setNode(int value, int x, int y) {grid[y * size + x] = value;}
	int getNode(int x, int y) {return grid[y * size + x];}
	int getSize() {return size;}

	bool isMagic() {return hasMagicSums() && hasMagicNumbers()}

	int getRowSum(int row)
	{
		int sum = 0; for(int aee = 0; aee < size; aee++)
		{sum += getNode(row,aee);} return sum;
	}

	int getColumnSum(int column)
	{
		int sum = 0; for(int aee = 0; aee < size; aee++)
		{sum += getNode(aee,column);} return sum;
	}

	int getCornerSum(int corner)
	{
		int sum = 0; for(int aee = 0; aee < size; aee++)
		{int iee = (corner > 0) ? (0 + aee) : (size - aee - 1);
		sum += getNode(iee, aee);} return sum;
	}

	int hasMagicSums()
	{
		int* allSums = new int[size * 2 + 2];
		for(int iee = 0; iee < size; iee++) {allSums[iee] = getRowSum(iee);}
		for(int oee = 0; oee < size; oee++) {allSums[size + oee] = getColumnSum(oee);}
		allSums[size * 2] = getCornerSum(-1); allSums[size * 2 + 1] = getCornerSum(1); int sampleSum = allSums[0];
		for(int aee = 1; aee < size * 2 + 2; aee++) {if(allSums[aee] != sampleSum) {return false;}}
		
		return true;
	}

	bool hasMagicNumbers()
	{
		bool* everyNumber = new bool[size * size];
		for(int aee = 0; aee < size * size; aee++) {everyNumber[aee] = false;}
		for(int iee = 0; iee < size; iee++) {for(int oee = 0; oee < size; oee++)
		{
			if(getNode(iee,oee) > size * size) {return false;}
			if(everyNumber[getNode(iee,oee) - 1] == true) {return false;}
			everyNumber[getNode(iee,oee) - 1] = true;
		}}

		return true;
	}
};