Question

C++ PROGRAM

1. Open the file input called "info.txt" read it and store the data in a vector.

2. Order the data by IP to perform the searches

3. Ask the user for the information search start and end IP's

- Example of data on the info text:

Jun 11 23:26:10 908.93.383.85:4940 Failed password for admin
Aug 2 05:13:39 355.45.117.69:4551 Failed password for root
Oct 24 02:32:14 852.37.168.72:6796 Illegal user

4. Display the records corresponding to those IPs

5. Store the result of the sorting in a file called "sorted.txt"

Answer 1

Approach

• Read from info.txt line by line using ifstream and store in a vector
• sort this vector using the generic sort method from STL library and provide the custom comparator
• In this custom comparator, we will first extract 4th word from each ip line (which is the ip string) and then compare thw two extracted ip string for sorting.
• once sorted, we will loop through the vector and write to sorted.txt using outfile and answer to user query to search for ip as well.

Code with inline comments in C++

#include <bits/stdc++.h> 
using namespace std;
string extract_ip(string ip_line){
        stringstream ss(ip_line);
        int count=4;
        string ip;
        while(count--){
                ss>>ip;
        }
        return ip;
}
bool IP_compare(string ip1, string ip2){
        return extract_ip(ip1)<extract_ip(ip2);
}
int main(){
        ifstream infile("info.txt");
        vector<string> allInfo;
        string line;
        //read all info
        while(getline(infile, line)){
                allInfo.push_back(line);
        }

        //sort allInfo using custom comparator
        sort(allInfo.begin(), allInfo.end(), IP_compare);

        //save sorted list in sorted.txt
        ofstream outfile("sorted.txt");
        for(string str:allInfo){
                outfile<<str<<endl;
        }
        string ip;
        do{
                cout<<"Enter Ip for Search or 0 to exit: ";
                
                //take input
                cin>>ip;
                //search for ip in ip_only vector
                bool found=false;
                for(string str:allInfo){
                        if(extract_ip(str)==ip)
                        {
                                cout<<"Found : "<< str<<endl;
                                found=true;
                                break;
                        }
                }
                if(!found)
                        cout<<"Not Found!"<<endl;
        }while(ip!="0");
        
}

Input/Output

info.txt

Jun 11 23:26:10 908.93.383.85:4940 Failed password for admin
Aug 2 05:13:39 355.45.117.69:4551 Failed password for root
Oct 24 02:32:14 852.37.168.72:6796 Illegal user

sorted.txt

Aug 2 05:13:39 355.45.117.69:4551 Failed password for root
Oct 24 02:32:14 852.37.168.72:6796 Illegal user
Jun 11 23:26:10 908.93.383.85:4940 Failed password for admin

Console Input/Output