The apmatrix class implements resizable two-dimensional arrays with safe subscripting. It is similar to the apvector class with the following differences --

• the constructors and the resize(..) function take two arguments, rows and cols, instead of one, size
  
• the length( ) function is replaced by two functions, numrows( ) and numcols( ).
  

Here are examples of the four apmatrix constructors - apmatrix words; // empty (zero-size) 2-D array of apstrings apmatrix table(10,2); // matrix of doubles with 10 rows and 2 columns apmatrix board(8,8,'X'); // 8 by 8 matrix of chars filled with 'X' apmatrix newboard ( board); // second 8 by 8 matrix copied from board x.

Here are some more examples of how to use apmatrices in a program -

#include "apmatrix.h"		// include the header file 
int rows = table.numrows( );	// determine the current number of rows of the matrix
int cols = table.numcols( );	// determine the current number of columns of the matrix
table.resize(5,3);		// set new dimensions of the matrix, truncating extra 
				// elements and filling new elements with default values,
				// (zeros for int, double, char types)
table[0][1] = 4.2;		// store 4.2 in the first row, second column of the matrix
				// at runtime checks that subscripts are within legal range

void fillMatrix(apmatrix &table);
	// Note that the & must be explicitly used when a matrix object is passed by reference.

void displayMatrix(const apmatrix &table);
	// To avoid unnecessary copying, do not pass an object by value .
	// Pass by reference using the keyword const to ensure the object cannot be changed