Question

C++ Data Structures TREES

You are to write a C++ program to count the frequency (number of occurrences) of n-grams in a text file. Definition of n-gram is simple: it is the number of consecutive letters in a given text. For example, for the word bilkent the 2-grams (bigrams) are bi, il, lk, ke, en, nt. You may ignore any capitalizations and assume that the text file contains only English letters 'a'...'z', 'A'…'Z', and the blank space to separate words. Your program should take the value of n as a parameter. While processing the input text, if your program encounters a word that has length smaller than the value of parameter n, you can simply ignore that word and process following words.

Answer 1

Thanks for the question.

Here is the completed code for this problem. Let me know if you have any doubts or if you need anything to change.
Thank You !!

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

void file_ngrams(char* filename, map<string,int> &frequency, int n){
  
   ifstream infile(filename);
   if (infile.is_open()){
      
       string file_line, word;
       while(getline(infile,file_line)){
           stringstream ss(file_line);
           while(ss>>word){
               if(word.size()<n)continue;
               for(int i=0; i<=word.size()-n;i++){
                   frequency[word.substr(i,n)]++;
               }
              
           }
       }
      
       infile.close();
      
   }else{
       cout<<"Unable to open the file "<<filename<<". Program will terminate now!";
       exit(1);
   }
  
  
}

int main(){
  
   const int NGRAM_SIZE = 3;
  
   map<string,int> frequency;
   char * filename ="F:\\abc.txt";
   file_ngrams(filename,frequency,NGRAM_SIZE);
   map<string , int >::iterator itr;
   for(itr=frequency.begin(); itr!=frequency.end();itr++)
   cout<<itr->first<<" frequency: "<<itr->second<<endl;
  
}

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