Programming Forums > Application Development > C++

Simplesouljah · Dec 4th, 2007, 6:28 PM

how do I get it to index where the values are located?

Ancient Dragon · Dec 4th, 2007, 6:44 PM

Quote:

Originally Posted by Simplesouljah

my outfile should print

The maximun value is ---- found at array ----
The minimum value is ---- found ar array ----
There are --- values---

I'm not understanding what I'm doing wrong....
what do I use to read the input infile?

I think your program is already doing that.

Quote:

Originally Posted by Simplesouljah

how do I get it to index where the values are located?

Don't understand that question.

Sane · Dec 4th, 2007, 6:50 PM

Quote:

Originally Posted by Simplesouljah

how do I get it to index where the values are located?

Instead of defining min and max as the value, define it as each index. Then refer to the value by indexing the array, and refer to the index as your min/max.

(Toggle Plain Text)

    ...

    if( myArray[i] > myArray[max])         
        max = i;     

    else if( myArray[i] < myArray[min])         
        min = i;  

    ++i;
}     

outFile << "The maximum value is " << myArray[max] << " found at array index position " << max << "." << endl;

lectricpharaoh · Dec 4th, 2007, 7:04 PM

Listen to Sane regarding using the index. You don't need to track the maximum value. You only need to track its position within the array, and this allows you to get the value from the array, since you know where it's stored.

Anyways, while other people were replying to you, I whipped up this. It's exactly what you need, but don't just use this for your homework. I'm doing it so you can see how it's done, and I'm only posting code because you've shown you're trying, but if you hand in my work rather than understanding it enough to do it yourself, it'll only hurt you in the long run.

 c++ Syntax (Toggle Plain Text) 
#include <fstream>
#include <iostream>
#include <string>
 
int main(void)
{
  std::ifstream inFile;
  std::ofstream outFile;
  int myArray[100],
      maximumValuePosition = 0,
      minimumValuePosition = 0,
      count = 0;
 
  inFile.open("inputNums.txt");
  if(!inFile)  // test if stream is valid, ie is file open?
  {
    std::cerr << "Unable to open input file, aborting..."
              << std::endl;
    return 1;
  }
 
  outFile.open("finalResults.txt");
  if(!outFile)
  {
    std::cerr << "Unable to open output file, aborting..."
              << std::endl;
    inFile.close();
    return 2;
  }
 
  while((count < 100) && (inFile >> myArray[count]))
    ++count;
 
  for(int x=0; x<count; ++x)
  {
    if(myArray[x] > myArray[maximumValuePosition])
      maximumValuePosition = x;
    if(myArray[x] < myArray[minimumValuePosition])
      minimumValuePosition = x;
  }
 
  if(count == 0)
  {
    outFile << "There were no values in the input file." << std::endl;
  }
  else
  {
    outFile << "The maximum value is "
            << myArray[maximumValuePosition]
            << ", found at array index " << maximumValuePosition
            << ".\n";
    outFile << "The minimum value is "
            << myArray[minimumValuePosition]
            << ", found at array index " << minimumValuePosition
            << ".\n";
    outFile << "There are " << count << " values." << std::endl;
  }
 
  inFile.close();
  outFile.close();
  return 0;
}
#include <fstream>
#include <iostream>
#include <string>

int main(void)
{
  std::ifstream inFile;
  std::ofstream outFile;
  int myArray[100],
      maximumValuePosition = 0,
      minimumValuePosition = 0,
      count = 0;

  inFile.open("inputNums.txt");
  if(!inFile)  // test if stream is valid, ie is file open?
  {
    std::cerr << "Unable to open input file, aborting..."
              << std::endl;
    return 1;
  }

  outFile.open("finalResults.txt");
  if(!outFile)
  {
    std::cerr << "Unable to open output file, aborting..."
              << std::endl;
    inFile.close();
    return 2;
  }

  while((count < 100) && (inFile >> myArray[count]))
    ++count;

  for(int x=0; x<count; ++x)
  {
    if(myArray[x] > myArray[maximumValuePosition])
      maximumValuePosition = x;
    if(myArray[x] < myArray[minimumValuePosition])
      minimumValuePosition = x;
  }

  if(count == 0)
  {
    outFile << "There were no values in the input file." << std::endl;
  }
  else
  {
    outFile << "The maximum value is "
            << myArray[maximumValuePosition]
            << ", found at array index " << maximumValuePosition
            << ".\n";
    outFile << "The minimum value is "
            << myArray[minimumValuePosition]
            << ", found at array index " << minimumValuePosition
            << ".\n";
    outFile << "There are " << count << " values." << std::endl;
  }

  inFile.close();
  outFile.close();
  return 0;
}

Sane · Dec 4th, 2007, 7:07 PM

Quote:

It's exactly what you need, but don't just use this for your homework.

Heh. Yeah right.

He'll look to make sure he fully understands it, then echo it into his course's dropbox.

But it's not my problem.

P.S. Your code tag really glitched out on my side for a second. The wrapping was broken, the font was different, and the background was white. Not sure what that was about.

lectricpharaoh · Dec 4th, 2007, 7:19 PM

Quote:

Originally Posted by Sane

Heh. Yeah right.

He'll look to make sure he fully understands it, then echo it into his course's dropbox.

Yeah, probably. But like you say, that's his problem.

I'd rather he ask questions if he doesn't understand, but hey- it's his grade.

Quote:

Originally Posted by Sane

P.S. Your code tag really glitched out on my side for a second. The wrapping was broken, the font was different, and the background was white. Not sure what that was about.

Yeah, I got that too, when I first posted, so I fixed it really quick. I also got it when I edited the code a bit (changed the output from 'x values in the file' to 'x values', as it won't read the entire file if there are more values than elements in the array). I think it's something with the context-highlighted code tags; if you use one of them, you'll notice after you preview your code, the edit box has the code, but not the start/end code tags. Weird.

Simplesouljah · Dec 4th, 2007, 8:37 PM

thanks for all your comments, yes I want a good grade, and I think I understand the help you've all given me. I will post my new code in a few...please let me know if I've understood all the advice that was given...

thank you all!!!!

Simplesouljah · Jan 24th, 2008, 1:08 PM

how do i post a new thread?

Sane · Jan 24th, 2008, 1:11 PM

Quote:

Originally Posted by Simplesouljah

how do i post a new thread?

That button is visible at the top of every forum index. The one I included in this post is from the C++ forum.

Dec 4th, 2007, 6:28 PM	#21
Simplesouljah Newbie Join Date: Oct 2007 Posts: 28 Rep Power: 0	Re: read integers from file into an array how do I get it to index where the values are located?

Dec 4th, 2007, 7:04 PM	#24
lectricpharaoh Caffeinated Neural Net Join Date: Jun 2005 Location: Dry west coast of Canada Posts: 920 Rep Power: 4	Re: read integers from file into an array Listen to Sane regarding using the index. You don't need to track the maximum value. You only need to track its position within the array, and this allows you to get the value from the array, since you know where it's stored. Anyways, while other people were replying to you, I whipped up this. It's exactly what you need, but don't just use this for your homework. I'm doing it so you can see how it's done, and I'm only posting code because you've shown you're trying, but if you hand in my work rather than understanding it enough to do it yourself, it'll only hurt you in the long run. c++ Syntax (Toggle Plain Text) #include <fstream> #include <iostream> #include <string> int main(void) { std::ifstream inFile; std::ofstream outFile; int myArray[100], maximumValuePosition = 0, minimumValuePosition = 0, count = 0; inFile.open("inputNums.txt"); if(!inFile) // test if stream is valid, ie is file open? { std::cerr << "Unable to open input file, aborting..." << std::endl; return 1; } outFile.open("finalResults.txt"); if(!outFile) { std::cerr << "Unable to open output file, aborting..." << std::endl; inFile.close(); return 2; } while((count < 100) && (inFile >> myArray[count])) ++count; for(int x=0; x<count; ++x) { if(myArray[x] > myArray[maximumValuePosition]) maximumValuePosition = x; if(myArray[x] < myArray[minimumValuePosition]) minimumValuePosition = x; } if(count == 0) { outFile << "There were no values in the input file." << std::endl; } else { outFile << "The maximum value is " << myArray[maximumValuePosition] << ", found at array index " << maximumValuePosition << ".\n"; outFile << "The minimum value is " << myArray[minimumValuePosition] << ", found at array index " << minimumValuePosition << ".\n"; outFile << "There are " << count << " values." << std::endl; } inFile.close(); outFile.close(); return 0; } #include <fstream> #include <iostream> #include <string> int main(void) { std::ifstream inFile; std::ofstream outFile; int myArray[100], maximumValuePosition = 0, minimumValuePosition = 0, count = 0; inFile.open("inputNums.txt"); if(!inFile) // test if stream is valid, ie is file open? { std::cerr << "Unable to open input file, aborting..." << std::endl; return 1; } outFile.open("finalResults.txt"); if(!outFile) { std::cerr << "Unable to open output file, aborting..." << std::endl; inFile.close(); return 2; } while((count < 100) && (inFile >> myArray[count])) ++count; for(int x=0; x<count; ++x) { if(myArray[x] > myArray[maximumValuePosition]) maximumValuePosition = x; if(myArray[x] < myArray[minimumValuePosition]) minimumValuePosition = x; } if(count == 0) { outFile << "There were no values in the input file." << std::endl; } else { outFile << "The maximum value is " << myArray[maximumValuePosition] << ", found at array index " << maximumValuePosition << ".\n"; outFile << "The minimum value is " << myArray[minimumValuePosition] << ", found at array index " << minimumValuePosition << ".\n"; outFile << "There are " << count << " values." << std::endl; } inFile.close(); outFile.close(); return 0; } __________________ A man's knowledge is like an expanding sphere, the surface corresponding to the boundary between the known and the unknown. As the sphere grows, so does its surface; the more a man learns, the more he realizes how much he does not know. Hence, the most ignorant man thinks he knows it all. - L. Sprague de Camp

Dec 4th, 2007, 8:37 PM	#27
Simplesouljah Newbie Join Date: Oct 2007 Posts: 28 Rep Power: 0	Re: read integers from file into an array thanks for all your comments, yes I want a good grade, and I think I understand the help you've all given me. I will post my new code in a few...please let me know if I've understood all the advice that was given... thank you all!!!!

Jan 24th, 2008, 1:08 PM	#28
Simplesouljah Newbie Join Date: Oct 2007 Posts: 28 Rep Power: 0	Re: read integers from file into an array how do i post a new thread?

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Programming Forums > Application Development > C++

read integers from file into an array