// file array1.h// A very simple templated array class// The C language doesn't provide a satisfactory dynamic array facility;// This is a very simple C++ one// do 1 and 2 dimensions// cut down version#include "include.h"#include "boolean.h"#include "myexcept.h"#ifndef ARRAY1_H                        // don't include twice#define ARRAY1_Htemplate <class T>class array1{private:protected:   T* a;                                // pointer to the array   int n;                               // length of the arraypublic:   array1() : a(0), n(0) {}             // build an array, length zero   array1(int xn);                      // build an array length xn   ~array1();                           // return the space to memory   T& operator()(int i);                // access element of the array   T operator()(int i) const;           // access element of constant array   void operator=(T ai);                // set the array equal to a constant   void operator=(const array1<T>& b);  // copy the elements of an array   array1(const array1<T>& b);          // new array equal to an existing one   int size() const { return n; }       // return the size of the array   void resize(int xn);                 // change the size of the array   T* data() { return a; }              // pointer to the data   const T* data() const { return a; }  // pointer to the data};// 2 dimensional array classtemplate <class T>class array2 : public array1<T>{protected:   int n_rows, n_cols;public:   array2(int x_n_rows, int x_n_cols);   T& operator()(int i, int j);			      // access element of the array   T operator()(int i, int j) const;			      // access element of constant array   void operator=(T ai);    // set the array equal to a constant   void operator=(const array2<T>& b);			      // copy the elements of an array   array2(const array2<T>& b);			      // make a new array equal to an existing one   int N_rows() const { return n_rows; }   int N_cols() const { return n_cols; }};// construct a new array of length xn. Check that xn is non-negative and// that space is availabletemplate <class T>array1<T>::array1(int xn) : n(xn){   if (n < 0) Throw(Logic_error("invalid array length"));   else if (n == 0) a = 0;   else   {      a = new T [n];      if (!a) Throw(Bad_alloc());   }}// destroy an array - return its space to memorytemplate <class T>array1<T>::~array1()   { if (a) delete [] a; }// access an element of an array; return a "reference" so elements// can be modified.// check index is within range// in this array class the index runs from 0 to n-1template <class T>void array1<T>::resize(int xn){   if (a) delete [] a;   n = xn;   if (n < 0) Throw(Logic_error("invalid array length"));   else if (n == 0) a = 0;   else   {      a = new T [n];      if (!a) Throw(Bad_alloc());   }}template <class T>T& array1<T>::operator()(int i){   if (i < 0 || i >= n) Throw(Logic_error("array index out of range"));   return a[i];}// same thing again but for arrays declared constant so we can't// modify its elementstemplate <class T>T array1<T>::operator()(int i) const{   if (i < 0 || i >= n) Throw(Logic_error("array index out of range"));   return a[i];}// set all the elements equal to a given valuetemplate <class T>void array1<T>::operator=(T ai)   {  for (int i = 0; i < n; i++) a[i] = ai; }// set the elements equal to those of another array.// check the arrays are of the same lengthtemplate <class T>void array1<T>::operator=(const array1<T>& b){   if (b.n != n) Throw(Logic_error("array lengths differ in copy"));   for (int i = 0; i < n; i++) a[i] = b.a[i];}// construct a new array equal to an existing array// check that space is availabletemplate <class T>array1<T>::array1(const array1<T>& b) : n(b.n){   if (n == 0) a = 0;   else   {      a = new T [n];      if (!a) Throw(Bad_alloc());      for (int i = 0; i < n; i++) a[i] = b.a[i];   }}// two dimensional arraytemplate <class T>array2<T>::array2(int x_n_rows, int x_n_cols)   : array1<T>(x_n_rows*x_n_cols), n_rows(x_n_rows), n_cols(x_n_cols) {}template <class T>T& array2<T>::operator()(int i, int j){   if (i < 0 || i >= n_rows || j < 0 || j >= n_cols)      Throw(Logic_error("array index out of range"));   return a[i+j*n_rows];}template <class T>T array2<T>::operator()(int i, int j) const{   if (i < 0 || i >= n_rows || j < 0 || j >= n_cols)      Throw(Logic_error("array index out of range"));   return a[i+j*n_rows];}template <class T>void array2<T>::operator=(T ai) { array1<T>::operator=(ai); }template <class T>void array2<T>::operator=(const array2<T>& b){   if (n_rows != b.n_rows && n_cols != b.n_cols)      Throw(Logic_error("array lengths differ in copy"));      for (int i = 0; i < n; i++) a[i] = b.a[i];}template <class T>array2<T>::array2(const array2<T>& b)   : array1<T>(b), n_rows(b.n_rows), n_cols(b.n_cols) {}#endif