CSC 272 - Software II: Principles of Programming Languages

Dr. R. M. Siegfried

A Program in C++ to Write An Array Of Integers In A Text File

// The first include is for the I/O Stream (console) library
#include	<iostream>
//The second include is for the file stream library
#include	<fstream>
//This enables the use of exit() in Turbo C++
#include	<stdlib.h>

using	namespace	std;

// Since you can't define constants inside a class declaration,
//	I defined them here
const int	FileNameLen = 30, ArrayLen = 20;

// The class array
class	array	{
public: // These functions are avaiable for use outside the class 
	array(void);
	//Inline functions are compiled into the code of the program
        // so they run faster than standard function calls
	inline int	getsize()	{return(size);}
	void		read(void);
	void		write(void);
private:
	//Private - available only to member functions
	int	x[ArrayLen];
	int	size;
};

// An initialization constructor - called automatically
// when an object from this class is defined
array::array(void)
{
	size = 0;
}

// Readarray() - 	Read the array
//			Arrays are passed by reference
void	array::read(void)
{
	size = 0;
	// Read each value 
	do	{
		cout << "Enter a value\t?";
		cin >> x[size++];	// Read an integer 
	} while (x[size-1] != 0 && size < ArrayLen);

	// Array indices run from 0 to n-1 
        size = (size == ArrayLen)? size - 2: size - 1;
}

void array::write(void)
{
	ofstream	outfile;		// file object
	char		filename[FileNameLen];	// Store the file name
						// as a character string
	cout << "Enter file name ->\t";
	cin >> filename;

	// Open the file
	outfile.open(filename);
	// If you can't open the file, print an error message
	//	and quit
	if (!outfile)	{
		cerr << "Cannot open " << filename << endl;
		exit(1);
	}



	for (int i = 0;  i < size;  i++)	
		outfile << "x[" << i << "] = " << x[i] << '\n';

}


int	main(void)
{
	array	myarray;

	myarray.read();
	myarray.write();
	return(0);
}

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