C++ program to print unique words in a file

Last Updated : 07 Aug, 2022

Write a function that takes a file name as argument and prints all unique words in it. We strongly recommend you to minimize your browser and try this yourself first The idea is to use map in STL to keep track of words already occurred.

C

// C++ program to print unique words in a string 
#include <bits/stdc++.h> 
using namespace std; 
 
// Prints unique words in a file 
void printUniquedWords(char filename[]) 
{ 
    // Open a file stream 
    fstream fs(filename); 
 
    // Create a map to store count of all words 
    map<string, int> mp; 
 
    // Keep reading words while there are words to read 
    string word; 
    while (fs >> word) 
    { 
        // If this is first occurrence of word 
        if (!mp.count(word)) 
            mp.insert(make_pair(word, 1)); 
        else
            mp[word]++; 
    } 
 
    fs.close(); 
 
    // Traverse map and print all words whose count 
    //is 1 
    for (map<string, int> :: iterator p = mp.begin(); 
        p != mp.end(); p++) 
    { 
        if (p->second == 1) 
            cout << p->first << endl; 
    } 
} 
 
// Driver program 
int main() 
{ 
    // Create a file for testing and write something in it 
    char filename[] = "test.txt"; 
    ofstream fs(filename, ios::trunc); 
    fs << "geeks for geeks quiz code geeks practice for qa"; 
    fs.close(); 
 
    printUniquedWords(filename); 
    return 0; 
} 