#include <iostream>
#include <cstdio>
#include <string>
#include <cctype>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;

int main() {
    FILE* file1 = fopen("test.in", "r");
    FILE* file2 = fopen("test.out", "w+");
    string str = "";
    string h = "hello";
    string temp_s = "";
    char temp;
    int a;
    int i = 0;

    if(!file1){
        cout << "Can't open file 'test.in'. You should create it!";
    }
    else{
        fseek(file1, 0, SEEK_END);
        long size = ftell(file1);
        rewind(file1);
        long cur_pos = 0;
        string checkWord;
        string buffer;
        string wordToFind = " hello ";

        while (cur_pos != size){
        //  cout << cur_pos<< "\t" << size << endl;
            fseek(file1, cur_pos, SEEK_SET);
            str = "";
            temp = '0';
            while(temp != '\n'){
                fscanf(file1, "%c", &temp);
                str = str + temp;
                cur_pos = ftell(file1);
                if(cur_pos == size) break;
                if(str == "\n") str = "";
                //cout << "\t\t" << str;
            }
            if(str != "")
            {

                buffer = str;
                buffer[buffer.length()-1] = ' ';
                buffer = " " + buffer;
                //cout << buffer << endl;

                for(int i = 0; i < buffer.length()-7; i++){
                    checkWord = "";
                    for(int j = 0; j < wordToFind.length(); j++){
                        checkWord = checkWord + buffer[i+j];
                    }
                //  cout << checkWord;
                    if(checkWord == wordToFind){
                        for(int a = 0; a < str.length(); a++){
                            fprintf(file2, "%c", str[a]);
                        }
                    }
                }
            }
        }
    }
    fclose(file1);
    fclose(file2);
    return 0;
}