How to fix code that counts letters in words?

[abc456]

This code works correctly. However I've been trying to get it to count and output the NUMBER of 3 letter words, 4 letter words etc. I'm not sure how to do this. I was messing around with the count but nothing I try works. Any advice is appreciated! Thanks in advance :)

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

int main()
{
	ifstream infile("testing.txt");
	string line;
	while (getline(infile, line))
	{
		istringstream iss(line);
		string word;
		int count = 0;
		while (iss >> word)
		{
				cout << word.size() << ": " << word << endl;
		}
		}
	system("pause");
	}

[kbw]

Check the word length. If it's 3, increment your count.

[mbozzi]

std::map<int, int> size_counts;
for (std::string tok; infile >> tok; ) size_counts[tok.size()]++;

[abc456]

@mbozzi I’m not sure how to use maps :( but thanks anyway. And @kbw I’m not sure how to check the word length that’s what I’m having trouble with :/

[lastchance]

If you don't want to use maps then you could use a normal int array to keep a tally, provided you set it to a decent size and have a check for word lengths exceeding this size. Alternatively, you could use a vector<int>, resized when necessary.

Use of word.size() will give you the length of each string separated by whitespace. If you want to remove punctuation like apostrophes, full stops, commas etc. then you would have to write a function taking a string as argument and scan its individual characters to check that they are alphabetic - use isalpha() from the header <cctype> - see the reference section of this website. You could also use the STL algorithm count_if should you not want to write your own loops.

#include <iostream>
#include <sstream>
#include <cctype>
#include <string>
using namespace std;

int wordLength( string word )
{
   int length = 0;
   for ( char c : word ) if ( isalpha( c ) ) length++;
   return length;
}

int main()
{
   const int MAXLENGTH = 10;  // Probably should set this bigger
   int freq[1+MAXLENGTH] = { 0 };
   int overlength = 0;

   string word;
   stringstream in( "This isn't easy. Three, two, one, go!!!" );
   while ( in >> word )
   {
      int length = wordLength( word );
      if ( length <= MAXLENGTH ) freq[length]++;
      else                       overlength++;
   }

   for ( int i = 1; i <= MAXLENGTH; i++ ) cout << i << ": " << freq[i] << '\n';
   cout << "There are " << overlength << " words of more than " << MAXLENGTH << " characters";
}

Here's an automatically-resizing one with a vector<int> to tally the frequencies and count_if to remove non-letters from "words".

#include <iostream>
#include <sstream>
#include <cctype>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

int wordLength( string word )
{
   return count_if( word.begin(), word.end(), ::isalpha );
}

int main()
{
   const int MAXLENGTH = 3;     // deliberately too small
   vector<int> freq( 1 + MAXLENGTH, 0 );

   string word;
   stringstream in( "This isn't easy. Three, two, one, go!!!" );
   while ( in >> word )
   {
      int length = wordLength( word );
      if ( length > MAXLENGTH ) freq.resize( 1 + length );
      freq[length]++;
   }

   for ( int i = 1; i < freq.size(); i++ ) cout << i << ": " << freq[i] << '\n';
}

1: 0
2: 1
3: 2
4: 3
5: 1

[E0p9LyTq]

How to split a multiple word std::string into the individual words, and know the length of each word:

#include <iostream>
#include <string>
#include <cstring> // for strtok & strlen

int main()
{
   std::string str = "This is a sentence, made up of individual words.  A big sentence.";
   std::cout << str << "\n\n";

   // create a C-string from the std::string.
   // parsing out individual words modifies the string.
   char *cstr = new char[str.length() + 1];
   std::strcpy(cstr, str.c_str());

   // define a pattern for word delimiters
   const char pattern[ ] = " ,.";

   // get the words
   char* token = std::strtok(cstr, pattern);
   while (token != NULL)
   {
      std::cout << std::strlen(token) << '\t' << token << '\n';

      // add code to count each sized word

      // get the next word
      token = std::strtok(NULL, pattern);
   }

   // clean up, it pays to be neat
   delete[] cstr;
}

This is a sentence, made up of individual words.  A big sentence.

4       This
2       is
1       a
8       sentence
4       made
2       up
2       of
10      individual
5       words
1       A
3       big
8       sentence

Now you just have to figure out how you are going to keep track of each sized word.

[abc456]

thanks everyone for your help i got it working :)