// AP Computer Science, A Exam, 1996, Question 4, part B in C++
// also AB Exam, question 2

 void RemoveCross(Mat & m, int R, int C)
 // precondition: 0 <= R < m.rows; 0 <= C < m.cols
 // postcondition: row with index R and column with index C
 //                have been removed from m
{
    int j,k;
    // shift all columns to the left once,
    // starting with index c

    for(j=0; j < m.rows; j++)
    {
	for(k=C; k < m.cols-1; k++)              // avoid bad index at right
	{
	    m.entries[j][k] = m.entries[j][k+1]; // shift left
	}
    }

    // now shift rows "up", matrix is a vector of vectors

    for(j=R; j < m.rows-1; j++)         // avoid bad index at bottom
    {
	m.entries[j] = m.entries[j+1];  // shift up
    }

    m.rows--;                           // change # entries in m
    m.cols--;
}