Chris help me im dying

/*
 *
 *
 *
 *
 */

#include <iostream>
#include <fstream>
#include <vector>
#include <string>
using namespace std;


vector<string> read_in(vector<string> words);
int total_characters(vector<string> words);
string longest_word(vector<string> words);
string shortest_word(vector<string> words);
int times_used(string input_word, vector<string> words);
string word_before(string input_word, vector<string> words);
string word_after(string input_word, vector<string> words);

int main(){
  vector<string> words;
  string input_word = "";
  double char_total = 0;
  double average = 0;
  string longest = "";
  string shortest = "";
  int word_used = 0;
  string before = "";
  ifstream in_file;
  ofstream out_file;

  words = read_in(words);
  if(words.size() == 0){
    cout << "ERROR: Please use a valid .txt file"<< endl;
    return 0;
  }
  cout << "Please give a word with exact captialization: ";
  cin >> input_word;
  char_total = total_characters(words);
  average = char_total/words.size();
  longest = longest_word(words);
  shortest = shortest_word(words);
  word_used = times_used(input_word, words);
  before = word_before(input_word, words);
  cout << char_total << "  " << average <<"  " << longest <<"  " << shortest <<"  "<< word_used <<endl;
}


/*The purpose of this function is to read in information from a file
 *
 *Parameters:
 *    vector<string>
 *
 *Return value:
 *    This will return a value depending on whether or not the txt file exists
 */
vector<string> read_in(vector<string> words){
  ifstream in_file;
  string file_name ="";
  string temp = "";
  cout << "Please give a file name: ";
  cin >> file_name;
  in_file.open(file_name.c_str());
  for(int i = 0; in_file >>temp; i++){
    words.push_back(temp);
  }
  return words;
}


/*This function will find the total amount of characters
 *
 *Parameters:
 *    vector<string>
 *
 *return value:
 *    This will return the amount of characters in a file
 */
int total_characters(vector<string> words){
  string temp = "";
  int total=0;
  for(int i = 0; i < words.size(); i++){
    temp = words[i];
    total += temp.length();
  }
  return total;
}

/*The purpose of this function is to find the longest word
 *
 *Parameters:
 *    vector<string>
 *return value:
 *    This returns the word that is the longest in the form of a string
 */
string longest_word(vector<string> words){
  string longest = "";
  for(int i = 0; i < words.size(); i++){
    if( i == 0){
      longest = words[i];
    }
    if(words[i].length() > longest.length()){
      longest = words[i];
    }
  }
  return longest;
}

/*The purpose of this function is to find the shortest word
 *
 *Parameters:
 *    vector<string>
 *return value:
 *    This returns the word that is the shortest in the form of a string
 */
string shortest_word(vector<string> words){
  string shortest = "";
  for(int i = 0; i < words.size(); i++){
    if( i == 0){
      shortest = words[i];
    }
    if(words[i].length() < shortest.length()){
      shortest = words[i];
    }
  }
  return shortest;
}

/*This function determines how many times a word is used that is given by the user
 *
 *Parameters:
 *     input_word: the word the user gives, vector<string> words: The entire file in the form of strings
 *
 *return value:
 *    How many times a certain string is used with exact capitalization
 */
int times_used(string input_word, vector<string> words){
  int counter = 0;
  for(int i = 0; i < words.size(); i++){
    if(words[i] == input_word){
      counter++;
    }
  }
  return counter;
}


string word_before(string input_word, vector<string> words){

}

string word_after(string input_word, vector<string> words){

}