I am trying to create a lexicon using an input file in C++

Question

I have a file.txt I want to create a function in C++ that can read the words in that file, and print each word and how many times they occur into a file2.txt

I am doing some research I know i can use the parser and writer, and also the map class, any help please?

bool Parser::hasMoreTokens() {
  if(source.peek()!=NULL){
    return true;
}
else{
     return false;
}
}

Step 1: *You* provide some code first – ildjarn Apr 11 '11 at 16:35 — ildjarn, Apr 11 '11 at 16:35

score 3 · Accepted Answer · answered Apr 11 '11 at 16:37

3

Is this home work? Look online for std::map, std:string, std::ifstream and std::ofstream.

answered Apr 11 '11 at 16:37

Charles Beattie

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score 1 · Answer 2 · answered Apr 11 '11 at 16:40

1

Read the file using ifstream, store into map of strings, use int as value of map and increment that each time you encounter a specific string. Next, write them to file using ofstream.

answered Apr 11 '11 at 16:40

Donotalo

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i need help implementing the parser function – Technupe Apr 11 '11 at 16:51
what does your parser funcion do? – Donotalo Apr 11 '11 at 16:59
it is a parser class that i have to implment, i want to make the parse class able to handle the Input operations – Technupe Apr 11 '11 at 17:01
do i use the ifstream to read from the file, i wrote source.open(filename); – Technupe Apr 11 '11 at 17:10
so i have functions in the parser.cpp that i have to implement – Technupe Apr 11 '11 at 17:12
Parser::Parser(string filename) the constructor – Technupe Apr 11 '11 at 17:12
Parser::~Parser() //destructor bool Parser::hasMoreTokens() //if there are any more tokens string Parser::nextToken() { //the next token void Parser::close() { //close the aprser – Technupe Apr 11 '11 at 17:13
@user570098 : The point you seem to be oblivious to is that no one here is going to do your homework for you. The best you can ask for is to be told what to search for and read up on, which has been done sufficiently. – ildjarn Apr 11 '11 at 17:21
i understand that, i just need to find out where i can find this information – Technupe Apr 11 '11 at 17:24
@user570098, enough information is already given. don't you think that? – Donotalo Apr 11 '11 at 18:00
also, google can show you enough tutorial. for example: http://www.cplusplus.com/doc/tutorial/files/ – Donotalo Apr 11 '11 at 18:01

score 0 · Answer 3 · answered Apr 13 '11 at 01:18

If you want to be efficient and accomplish this in less possible amount of lines, but by using standard library, try this:

#include <fstream>
#include <iostream>
#include <iterator>
#include <set>
#include <string>

int main()
{
     std::ifstream f("text.txt");
     std::istream_iterator<std::string> eof;
     std::multiset<std::string> words( std::istream_iterator<std::string>(f) , eof);

     std::ofstream f_out("text_output.txt");
     for( std::multiset<std::string>::iterator i = words.begin(); i!=words.end(); i = words.upper_bound(*i) )
          f_out << "the word " << *i << " found " << words.count(*i) << " times\n";

}

This code grabs the file named "text.txt" and outputs result to "text_output.txt"

Contents of "text.txt":
can can can I I I do this properly?
How many times do I need to program one thing to remember it?
Contents of "text_output.txt":
the word How found 1 times
the word I found 4 times
the word can found 3 times
the word do found 2 times
the word it? found 1 times
the word many found 1 times
the word need found 1 times
the word one found 1 times
the word program found 1 times
the word properly? found 1 times
the word remember found 1 times
the word thing found 1 times
the word this found 1 times
the word times found 1 times
the word to found 2 times

Good resource to learn fantastic ways of using c++ efficiently is a book called Accelerated c++.

Regards,

I am trying to create a lexicon using an input file in C++

3 Answers3