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check if values are in map

ReaperSoul (52)
hi im trying to create a program that counts words from a .txt file and any time it encounters a new word it starts counting how many of that word are in the file as well but i can't seem to find a way to do this.
Last edited on
Repeater (3046)
A map comes to mind.

Read word. Check if word is in map. If not, create new entry in map (key = new word) with value zero. If it is in the map, increment the entry with key == word by one.
ReaperSoul (52)
do you mind showing me an example i haven't worked with maps before each line of the file has one word on it
Last edited on
Repeater (3046)
Something like:

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map<string, int> theMap;
...
if (theMap.find(word) != theMap.end())
{
  theMap[word]++;
}
else
{
  theMap[word] = 0;
}
ReaperSoul (52)
thank you i appreciate your help i think this will work i just need to read each line of the .txt file and put the word on that line in the map. i think.
Thomas1965 (4571)
@Repeater
theMap[word] = 0; shouldn't the count then be 1 if it is added?
Repeater (3046)
Sure. Something like.
ReaperSoul (52)
im having another problem im trying to check that my words are being placed into the map
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#include <iostream>
#include <fstream>
#include <string>
#include <map>
using namespace std;

int main () {
  string line;
  string word;
  ofstream outputFile("test.txt");
  ifstream file ("tim.txt");
  map<string,int> words;
  string it;
  if (file.is_open())
  {
    while ( getline (file,line) )
    {
    words.insert(make_pair(line,1));
    }
    file.close();
  }
  return 0;
}
Repeater (3046)
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if (theMap.find(word) != theMap.end()) // is the string already in the map?
{
  theMap[word]++;
}
else
{
  theMap[word] = 1;
}
Thomas1965 (4571)
With getline you read the whole line, not sure if you really want it.
Try this:
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#include <iostream>
#include <fstream>
#include <string>
#include <map>
#include <cstdio>

using namespace std;

int main()
{
  map<string, int> words;
  ifstream src("words.txt");
  if (!src)
  {
    perror(nullptr);
    return errno;
  }
  string word;
  while (src >> word)
     words[word]++;

  for (auto& p : words)
  {
    cout << p.first << "\t" << p.second << "\n";
  }
  return 0;
}
ReaperSoul (52)
i do want to read the whole line there is one word per line in the file but im trying to make sure that my words are getting inserted into the map
ReaperSoul (52)
i believe i have a working version
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#include <iostream>
#include <fstream>
#include <string>
#include <map>
using namespace std;

int main () {
  string line;
  ofstream outputFile("test.txt");
  ifstream myfile ("tim.txt");
  map<string,int> words;
  string it;
  if (myfile.is_open())
  {
    while ( getline (myfile,line) )
    {
          if (words.find(line) != words.end()) 
{
  words[line]++;
  cout<<line<<endl;
     cout<<"word exists"<<endl;
}
else
{
  words[line] = 1;
   cout<<line<<endl;
    cout<<"word dosent exist"<<endl;
}
    }
    myfile.close();
  }

  return 0;
}
Last edited on
ReaperSoul (52)
i now need to print the all of the keys and values from the map to the console if i could get some help with that.
ReaperSoul (52)
nvm i figured it out
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