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;
} |
Output:
code practice qa quiz
Time complexity: O(nlogn) where n is no of words in given file
Auxiliary Space: O(n)
Thanks to Utkarsh for suggesting above code.
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