Thread: Another homework assiment..

well, seeing as you didn't give enough code to even give us the errors you're getting or the files you're using, I used this code:

Code:

#include <iostream>
#include <string>
#include <fstream>
#include <cstdlib>
#include <cassert>

using namespace std;

void Survival_of_the_Fittest();
void Copyfrom(string from_name, string to_name);

int main()
{
	Survival_of_the_Fittest();
	return 0;
}

void Survival_of_the_Fittest ()
{
     int exit=0;//the abort variable
     int flag=0;//the flag for the count of characters right
     int lem_length=1;//the lengh of the file needs to be reproduced
     char ch_lem;//buffer char
     char ch_copy;//buffer char
     char random;//the randomly generated char 
     int location;//the location to write to
     
     time_t seconds;//seeding the time for randomly generating
     time(&seconds);
     srand(seconds); 
     
     
     while (flag!=lem_length)//while count is not lengh
     {
           ifstream icopy;//creat the read file
           ofstream outfile;//creat the out file
           icopy.open("tempsecond.txt");//open read
           outfile.open("temp.txt");//open write
           
           ifstream ilemony;//the file that needs to be reproduced
           ilemony.open("lemony.txt");//open it
     
           ilemony.seekg(0,ios::end);//put the pointor to the end
           lem_length=ilemony.tellg();//assign the number of chars to length
           
           ilemony.seekg(0);//put to begining
           icopy.seekg(0);
           //flag=0;
           
           while (!ilemony.eof())//while the original file not end of file
           {
                 ilemony.get(ch_lem);//get ch from original
                 icopy.get(ch_copy);//get ch from read
                 
                 if (ch_lem==ch_copy)//if ch read same as ch original
                 {
                      flag++;//add one to count
                 }
                 else 
                 {  
                      random=rand()% 96 + 32;//generate all the characters
                      if (random==127)//if 127 which is useless
                         random=10;   //then change to end line
                      location=ilemony.tellg();//get the location we are at
                      outfile.seekp(location);//put the write file pointer to location  
                      outfile<<random;//print into the file
                 }
           }
           cout<<"The number correct is: "<<flag<<endl;//output the correct number
           ilemony.close();//close original
           outfile.close();//close out
           icopy.close();//close read
           Copyfrom("temp.txt","tempsecond.txt");//make them exactly same
     }
}

void Copyfrom(string from_name, string to_name)
{
      char ch;//buffer
      int from_length;//length
      
      ofstream to;//creates file
      to.open(to_name.c_str());
      
      ifstream from;//creats another one
      from.open(from_name.c_str());
      
      assert (!from.fail());//check that not fail to open
      assert (!to.fail());
         
      from.seekg(0);
      
      while(! from.eof()) //till not end of file
      {
              from.get(ch);//print that
              to<<ch;
      }
      to.close();//close them both
      from.close();
}

with this file:

Code:

Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Duis sollicitudin ante et nisi. Suspendisse potenti. Donec viverra neque sed orci. Nullam suscipit dolor vitae turpis. Aenean nisi. Phasellus feugiat, ante nec semper aliquet, augue dolor cursus purus, sit amet vestibulum magna purus et est. In laoreet, est nec vestibulum lobortis, ligula augue gravida neque, et malesuada risus ipsum sit amet est. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; In semper. Praesent sed eros eget tellus venenatis euismod. Donec posuere metus eu dui. Vivamus nec tortor.

Quisque ac diam a nunc accumsan tristique. Praesent lectus. Curabitur imperdiet est pulvinar mauris. Vestibulum leo urna, varius sit amet, ullamcorper in, ultrices eu, dolor. Integer felis diam, mattis a, tincidunt in, consectetuer ut, sapien. Sed venenatis rhoncus velit. Nulla facilisi. Duis nec elit fringilla sem viverra gravida. Cras vitae sem euismod arcu luctus pellentesque. Cras posuere nonummy felis. Nullam fermentum lacus. Vivamus mi tellus, faucibus ut, molestie et, sollicitudin non, eros. Donec imperdiet ante ac diam. Fusce eu eros. Pellentesque tortor. Phasellus sed erat eu est malesuada bibendum.

Aenean dictum. Proin et quam. Curabitur pulvinar pretium tortor. In hac habitasse platea dictumst. Nunc faucibus. Fusce fringilla, magna a dignissim vestibulum, ipsum dolor ornare velit, id fermentum neque ante non odio. Morbi blandit dictum dui. Nam risus enim, aliquam sit amet, interdum eget, ullamcorper vitae, nibh. Vivamus enim libero, luctus vitae, tempus eget, tristique et, tortor. Donec magna mi, tincidunt eu, posuere vel, vulputate eu, mi. Nulla at ante vitae est pulvinar faucibus. Nullam pretium. Phasellus velit mauris, varius in, dapibus et, tempor non, quam. Nam eget augue nec est tempor semper. Vivamus eleifend tortor in tellus. Pellentesque ultricies dui sit amet erat. Quisque non tellus pellentesque arcu porttitor ultrices. Aenean faucibus vehicula odio. Donec sed velit.

Nam malesuada justo ut arcu pellentesque mattis. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Cras nec urna sed nunc posuere tincidunt. Nullam sollicitudin, tellus mollis congue porta, nisl ipsum tempor ante, nec sagittis turpis dui in enim. Nullam consectetuer luctus orci. Sed mattis vehicula elit. Nam venenatis odio sit amet metus. Duis quis nunc. Proin egestas augue in nisl. Aliquam vulputate quam. Vestibulum iaculis volutpat nunc. Fusce pharetra. Aliquam malesuada sem nec lectus volutpat ornare. Aliquam id diam eget pede lacinia nonummy. Sed neque massa, porta at, dictum sit amet, pharetra vitae, metus. Aenean quis ligula non enim varius rutrum. Suspendisse ipsum erat, convallis non, mattis pulvinar, interdum a, lacus. Duis consectetuer purus ac nunc. Fusce non nibh nec massa congue porttitor. Etiam vestibulum, diam eu mollis dignissim, justo massa nonummy sem, volutpat consequat nulla tellus id ipsum.

Praesent ullamcorper, metus et placerat suscipit, ante nunc suscipit dui, in auctor justo pede nec ipsum. Nullam quis diam. Vestibulum commodo lacus eu arcu. Suspendisse potenti. Vestibulum arcu. Aliquam nonummy metus vel neque. In pellentesque interdum ligula. Aliquam erat volutpat. Cras tortor nibh, lobortis quis, egestas in, pharetra ullamcorper, sem. Aenean ultricies nulla id lacus. Vestibulum massa erat, scelerisque et, tincidunt sit amet, ultricies a, ipsum. Donec quam purus, eleifend ac, vulputate sed, auctor sit amet, tellus.

This is what I get when I compile:

Code:

jshao@MCP ~/Programming/C++/test $ g++ test.cpp -Wall -W -ansi -pedantic -o test.exe
test.cpp: In function `void Survival_of_the_Fittest()':
test.cpp:20: warning: unused variable `int exit'
test.cpp: In function `void Copyfrom(std::basic_string<char,
   std::char_traits<char>, std::allocator<char> >, std::basic_string<char,
   std::char_traits<char>, std::allocator<char> >)':
test.cpp:80: warning: unused variable `int from_length'

and this is what I get when I run:

Code:

jshao@MCP ~/Programming/C++/test $ ./test.exe
The number correct is: 0

I suggest you post more code and your files, because there's just waaay too much that can be wrong at this point.

and wtf does "then we have to randomly regenerate exactly same content." mean?

edit: oh yeah, and assert() is yucky... handle the errors in your own way

Originally Posted by kennny2004

Well the "then we have to randomly regenerate exactly same content." means that we have to creat another .txt file and keep generating untill the file we creat is exactly the same. And for the code thats the only to function used the rest is main function calling it. So there is nothing else. And thanks for trying. Gota bug the teacher tommorow.

so the code I have is the same code you have? if so, just show me your input files... I can probably help you fix it. and for the record, that is the most insanely useless project I have ever heard of. Unless of course you're doing some kind of research into the PRNG...

Okay, I almost did your homework for you. It looks like you needed to time your code, and I didn't do that. All I did was count the number of iterations of the interior loop it took to get the file right. I also didn't throw in any checks, so if the files don't open, it won't really tell you what's wrong.

And I'm pretty sure that if you used this code your professor will know it's not your own... I passed streams between functions, and it doesn't look like you're up to that level yet

Code:

#include <iostream>
#include <fstream>
#include <ctime>
#include <cstdlib>

long int copy(std::fstream&in, std::fstream&out);
bool check(std::fstream&orig, std::fstream&copy);

int main()
{
	srand(static_cast<unsigned int>(time(0)));
	
	std::fstream in("test.in",std::ios::in);
	std::fstream out("test.out",std::ios::out|std::ios::trunc);

	long int iter=copy(in,out);

	in.close();
	in.clear();
	in.open("test.in",std::ios::in);
	out.close();
	out.clear();
	out.open("test.out",std::ios::in);

	if(check(in,out))
	{
		std::cout<<"Files Successfully Copied in "<<iter<<" iterations"
			<<std::endl;
	}
	else
	{
		std::cout<<"Error in File Copy"<<std::endl;
	}

	in.close();
	out.close();

	return 0;
}

long int copy(std::fstream&in, std::fstream&out)
{
	char ch;
	char ch2;
	long int iter=0;
	
	while(in.get(ch))
	{
		do
		{
			ch2=static_cast<char>(rand());
			iter++;
		}
		while(ch2!=ch);
		out<<ch2;
	}

	return iter;
}

bool check(std::fstream&orig,std::fstream&copy)
{
	char ch;
	char ch2;
	
	while(orig.get(ch) && copy.get(ch2))
	{
		if(ch!=ch2)
		{
			return false;
		}
	}
	return true;
}

it also doesn't print the file out to standard output. So why did I even do it? So you can read it and learn the algorithm, which is where I suspect you're having the problem... So I leave it to you.

oh yeah, and there's no comments

OO Wow thanks for that I will check and see what i did wrong and try to get something out of your code. And once again thanks for the time and all the help. I am almost there But not yet. Thanks Once again.

K after looking at it for an hour All i can say is . I am so confused not funny one thing is don't u need to create another file for the to copy to to avoid trncation. And umm why don't u used using namespace std; Just our of curiosity. Does it make it slower or anything?. Thanks

Originally Posted by kennny2004

And umm why don't u used using namespace std; Just our of curiosity. Does it make it slower or anything?. Thanks

It unnecessarily pollutes the global namespace with a lot of useless crap. For small programming projects it doesn't hurt by having "using namespace std" in the code. For larger projects there is a greater likelihood for object naming conflicts and you should do without it. Overall, you should try to avoid it where possible.

because reading and writing takes a long time.

Think about it this way - every time you change something in a file, you're telling your processor to send something to your harddrive, which has to find the bit on the disk, physically move to it, and change it. if you do it the way I did it, the processor just changes a bit in memory, and the writing is done later on.

you're also thrashing your disks your way - a whole lot of unessecary reading/writing in the same place, which wears your disks down and actually shortens the life a little.