Listing PG6.cpp...

// Ben Harris
// Main: Program6

#include <iostream>
#include <string>
#include <cstdlib>
#include <algorithm>
#include <fstream>
#include "PG6.h"
using namespace std;

int main(int argc, char **argv){
	string fn = "";
	streampos fsz;
	cout << "Enter the name of the file that you want to sort." << endl << "File Name: ";
	getline(cin, fn);
	fstream f (fn, ios::in | ios::out | ios::binary);
	if (f.is_open()){

		char * recordsz = new char[4];
		f.read(recordsz, (streamsize) 4);
		int rsz = atoi(recordsz);
		f.seekg(0, f.end);
		fsz = f.tellg();
		int recordcnt = ((int)fsz-4) / rsz;
		f.seekg(0, f.beg);
		//cout << "File size: " << fsz << " Record size: " << rsz << " Number of records: " << recordcnt << endl;
		int d = recordcnt;
		while (d > 1){
			d = (d == 2) ? 1 : d % 2 == 1 ? (d + 1) / 2 : d % 4 == 0 ? d / 2 + 1 : d / 2 + 2;
			for (int i = d; i < recordcnt; i++)
				for (int j = i - d; j >= 0 && readstring(f,j,rsz) > readstring(f,j + d,rsz); j -= d){
				string t = readstring(f,j,rsz);
				writestring(f, j, rsz, readstring(f,j + d,rsz));
				writestring(f, j+d, rsz, t);
				}
		}
	}
	else cout << "Error: file could not be opened or does not exist." << endl;
	system("pause");
}

string readstring(fstream &f, int recordpos, int len){
	char* t = new char[len];
	f.seekg(recordpos*len + 4, ios::beg);
	f.read(t, len);
	return (string)t;
}

void writestring(fstream &f, int recordpos, int len, string s){
	f.seekg(recordpos*len + 4, ios::beg);
	char * t = new char[s.length()];
	for (unsigned int i = 0; i < s.length(); i++) t[i] = s[i];
	f.write(t, len);
}



Listing PG6.h...

// Ben Harris
// Header for program 6

#ifndef _PG6_
#define _PG6_

#include <iostream>
#include <string>
#include <cstdlib>
#include <fstream>
using namespace std;

int main(int argc, char **argv);
//void shellsort(string* s, int sz);
string readstring(fstream &f, int recordpos, int len);
void writestring(fstream &f, int recordpos, int len, string s);

#endif


Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\apoe\Desktop\Grading Folder>cppcompileall PG6.exe
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\apoe\Desktop\Grading Folder>"C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\vcvarsall.bat" x86
Setting environment for using Microsoft Visual Studio 2010 x86 tools.

C:\Users\apoe\Desktop\Grading Folder>cl /Tp "PG6.cpp" /O2 /EHsc /W2 /Za /link /OUT:PG6.exe
PG6.cpp
Microsoft (R) Incremental Linker Version 10.00.40219.01
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:PG6.exe
/OUT:PG6.exe
PG6.obj

C:\Users\apoe\Desktop\Grading Folder>Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.00.40219.01 for 80x86
Copyright (C) Microsoft Corporation.  All rights reserved.


C:\Users\apoe\Desktop\Grading Folder>copy /y "C:\Grading\Classes\CS201-02-14F\PG6\test1.txt" .
        1 file(s) copied.

C:\Users\apoe\Desktop\Grading Folder>PG6.exe < "C:\Grading\Classes\CS201-02-14F\PG6\PG6-1.in"
Enter the name of the file that you want to sort.
File Name: Press any key to continue . . .

C:\Users\apoe\Desktop\Grading Folder>cmp test1.txt C:\Grading\Classes\CS201-02-14F\PG6\test1.out
Files are the same.

C:\Users\apoe\Desktop\Grading Folder>
C:\Users\apoe\Desktop\Grading Folder>copy /y "C:\Grading\Classes\CS201-02-14F\PG6\test2.txt" .
        1 file(s) copied.

C:\Users\apoe\Desktop\Grading Folder>PG6.exe < "C:\Grading\Classes\CS201-02-14F\PG6\PG6-2.in"
Enter the name of the file that you want to sort.
File Name: Press any key to continue . . .

C:\Users\apoe\Desktop\Grading Folder>cmp test2.txt C:\Grading\Classes\CS201-02-14F\PG6\test2.out
Files are the same.

C:\Users\apoe\Desktop\Grading Folder>
C:\Users\apoe\Desktop\Grading Folder>copy /y "C:\Grading\Classes\CS201-02-14F\PG6\test3.txt" .
        1 file(s) copied.

C:\Users\apoe\Desktop\Grading Folder>PG6.exe < "C:\Grading\Classes\CS201-02-14F\PG6\PG6-3.in"
Enter the name of the file that you want to sort.
File Name: Press any key to continue . . .

C:\Users\apoe\Desktop\Grading Folder>cmp test3.txt C:\Grading\Classes\CS201-02-14F\PG6\test3.out
Files are the same.

C:\Users\apoe\Desktop\Grading Folder>
C:\Users\apoe\Desktop\Grading Folder>exit

Undercommented.

45/50.