cin을 오버로딩했는데 입력을 받지 않고 그냥 지나갑니다.

int main()
{
	Matrix A, B;	
	cin >> A;
	fflush(stdin);	
	cin >> B;	
	//A+B;
	return 0;
}

istream& operator >> (istream& is, Matrix& matrix)
{	
	Triple s;
	int p;
	is >> s.row >> s.col >> s.value;  //문제의 부분!!!!
	if(s.row > s.col)p = s.row;
	else p = s.col;
	matrix.headnode = new MatrixNode(FALSE, &s);		
	if(p == 0){
		matrix.headnode -> right = matrix.headnode;
		return is;
	}	
	MatrixNodePtr *head = new MatrixNodePtr[p];
	for (int i=0; i<p; i++)
		head[i] = new MatrixNode(TRUE, 0);
	int CurrentRow = 0;
	MatrixNode *last = head[0];
	for (i=0; i<s.value; i++){
		Triple t;
		is >> t.row >> t.col >> t.value;
		if(t.row > CurrentRow){
			last->right = head[CurrentRow];
			CurrentRow = t.row;
			last = head[CurrentRow];
		}	
		last = last->right = new MatrixNode(FALSE, &t);
		head[t.col]->next = head[t.col]->next->down = last;
	}	
	last->right = head[CurrentRow];
	for(i=0; i<s.col; i++)
		head[i]->next->down = head[i];
	head[p-1]->next = matrix.headnode;
	matrix.headnode->right = head[0];
	delete[]head;
	return is;
}