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Apr 8th, 2009

Reading in Character Frequences help

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Hi I was wonder if anyone could help with this problem I am receiving. My program is suppose to read in any character frequencies from a file, even spaces and /n. My problem is that is reading an extra character that I can figure out.
I had inputed a text file that aab no spaces and no new lines. It would out put as
The Character Frequencies are
1
a 2
b 1
which throws everything off.
This program will make a huffman code out of the frequencies, but it messes up everything cause of the unknown space and 1. Here is what I've been using for my read input. If anyone could take a look I would really appreciate it.

C++ Syntax (Toggle Plain Text)
#include <cstdio>
#include <fstream>
#include <iostream>
#include <cstring>
//tab space 1
using namespace std;
 
 
void phase1(int array[], ifstream& in)
{
  int c = 0;  
  for(int i = 0; i < 255; i++)
  {
  	array[i] = 0;
  }
  while(c != EOF)
  {
    c = in.get();
    c = (int)c;
    array[c] = array[c]+1;
  }
}
 
//phase2 prints the frequency of each character
//read from a text file
void phase2(int array[])
{
  int n = 0;
 
  cout << "The character frequencies are: " << '\n';
 
  while(n < 255)
  {
    if(array[n] != 0)
    {
      cout << (char)n; 
      cout << " ";
      cout << array[n];
      cout << "\n";
    }
    n = n + 1;
  }
}
 
int main(int argc, char* argv[])
{
  ifstream in(argv[1]);
  int array[256];
  phase1(array, in);
  phase2(array);
  return 0;
}
#include <cstdio>
#include <fstream>
#include <iostream>
#include <cstring>
//tab space 1
using namespace std;


void phase1(int array[], ifstream& in)
{
  int c = 0;  
  for(int i = 0; i < 255; i++)
  {
  	array[i] = 0;
  }
  while(c != EOF)
  {
    c = in.get();
    c = (int)c;
    array[c] = array[c]+1;
  }
}

//phase2 prints the frequency of each character
//read from a text file
void phase2(int array[])
{
  int n = 0;
  
  cout << "The character frequencies are: " << '\n';
  
  while(n < 255)
  {
    if(array[n] != 0)
    {
      cout << (char)n; 
      cout << " ";
      cout << array[n];
      cout << "\n";
    }
    n = n + 1;
  }
}

int main(int argc, char* argv[])
{
  ifstream in(argv[1]);
  int array[256];
  phase1(array, in);
  phase2(array);
  return 0;
}

yingfo

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Apr 8th, 2009

Re: Reading in Character Frequences help

I actually don't understand your question ...

tux4life

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Apr 8th, 2009

Re: Reading in Character Frequences help

it will read in some imaginary output I guess is the best way the say it.
Since there are no spaces or new lines, its reading something that it shouldn't
that's why I get
1
a 2
b 1
does that make sense?

yingfo

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Apr 8th, 2009

Re: Reading in Character Frequences help

I guess the unwanted number '1' is the number of newlines your program has counted so far ...

tux4life

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Apr 8th, 2009

Re: Reading in Character Frequences help

In your function phase1 you've to change everything in the while loop to:

C++ Syntax (Toggle Plain Text)
c = in.get();
/* We use an if-statement to ignore the newlines */
if(c != '\n')
{
        c = (int)c;
	array[c] = array[c]+1;
}
c = in.get();
/* We use an if-statement to ignore the newlines */
if(c != '\n')
{
        c = (int)c;
	array[c] = array[c]+1;
}

It should work now !

Last edited by tux4life; Apr 8th, 2009 at 11:13 am.

tux4life

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Apr 8th, 2009

Re: Reading in Character Frequences help

If I were to make this, I wouldn't use array's, but I'd use a map:

C++ Syntax (Toggle Plain Text)
#include <iostream>
#include <string>
#include <map>
 
using namespace std;
 
int main(void)
{
    //store
    string str = "aab";
    map<char,int> total;
    for (unsigned i =0; i < str.size(); i++)
        total[str[i]] += 1;
    //show   
    map<char,int>::iterator it;
    for (it = total.begin(); it != total.end(); ++it)
        cout << "'" << it->first << "': " << it->second << " times\n"; 
    return 0;
}
#include <iostream>
#include <string>
#include <map>

using namespace std;

int main(void)
{
    //store
    string str = "aab";
    map<char,int> total;
    for (unsigned i =0; i < str.size(); i++)
        total[str[i]] += 1;
    //show   
    map<char,int>::iterator it;
    for (it = total.begin(); it != total.end(); ++it)
        cout << "'" << it->first << "': " << it->second << " times\n"; 
    return 0;
}

nice and simple

Nick Evan

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