#include <stdio.h>
#include <stdlib.h>

typedef   double **   matrix;
typedef   double *    row;
typedef   double      elem;

.....

matrix   get_matrix_space(int m, int n);
void     release_matrix_space(matrix a);
void     fill_matrix(matrix a, int m, int n);
void     prn_matrix(const char *s, matrix a, int m, int n);