Question

I intend to find out if any permutation(s) of a user inputted string is a valid word in a text file with few words.

After inputting string, nothing happens! What’s wrong with “if” stmt or what? Also, if I write an else that is executed which means control never reached to if even though I input words present in the list.txt

What can I try to fix this?

//check if any permutation of a user inputted word are in a pre defined text file

    #include <iostream>
    #include <fstream>
    #include <vector>

    using namespace std;

    int main(){
        cout<<"Enter a word to check for the presence of any
        << of its permutation in a file \n"; 
        string word; 
        cin>>word; 
        sort(word.begin(), word.end()); 
        vector<string> str; 
        do str.push_back(word);
        while( next_permutation(word.begin(),word.end()) );                  

        ifstream readFile("list.txt");
        string line;
        while(readFile>>line){
              for (int i = 0; i < str.size(); ++i){
                  if(line==str[i]){
                     cout << "found " << str[i] << endl;
                     break;
                  }
              }
        }
        system("pause");
        return EXIT_SUCCESS;
    }

Answer 1

1) You should store the strings to search in a vector.

vector<string> words_to_search;
sort(word.begin(), word.end()); 
do 
   words_to_search.push_back(word);
while (next_permutation(word.begin(), word.end()));

Then you can loop through them like this

for (vector<string>::iterator i = words_to_search.begin();
     i != words_to_search.end(); ++i)
{
    string search_word = *i;
    // search for search_word
    ...
}

2) To compare your strings just use ==

if (line == search)

You might need to remove leading and trailing white space from line first though.