Solved

c++ output .txt file

Posted on 2009-05-03
2
878 Views
Last Modified: 2013-12-14
I need help quickly.  I am trying to get this program to do four things, using the command line prompt encrypt a .txt file, decrypt a .txt file, output the first five lines of text, output the last five lines of text.  I've got decrypting and encrypting going, but I can't figure out how to display the lines of the .txt file.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
const int htlen=5;
const int ascLEn=256;
const int ecryptCode=10;
void print_usage()
{
      cout<<"Usage"<<endl;
      cout<<"      lab12 -e file1 file2  Encrypt file1 and write cyphertext to file2"<<endl;
      cout<<"      lab12 -d file1 file2  Decrypt file1 and write paintext to file 2"<<endl;
      exit(1);
}
int main(int argc, char* argv[])
{
      if (argc != 4)
            print_usage();
            if (strcmp(argv[1], "-e") !=0&&strcmp(argv[1], "-d")!=0)
                  print_usage();
      ifstream inData;
      ofstream outData;
      inData.open(argv[2]);
      outData.open(argv[3]);
      if (inData.fail()||outData.fail())
      {
            cout<<"File open error!"<<endl;
            return 1;
      }
      string s;
      if (strcmp(argv[1], "-e")==0)
      {
            while (!inData.eof())
            {
                  getline(inData, s);
                  for (int i=0;i<s.length();i++)
                        s[i]=char(s[i] + ecryptCode)%ascLEn;
                  outData<<s;
                  if (!inData.eof())
                        outData<<endl;
            }
      }
      else
      {
            while (!inData.eof())
            {
                  getline(inData, s);
                        for (int i=0;i<s.length();i++)
                              s[i]=char(s[i]+ascLEn-ecryptCode)%ascLEn;
                  outData<<s;
                  if (!inData.eof())
                        outData<<endl;
            }
      }
      inData.close();
      outData.close();
      return 0;
      system("pause");
}
0
Comment
Question by:scuzzo
2 Comments
 
LVL 39

Accepted Solution

by:
itsmeandnobodyelse earned 500 total points
ID: 24292907
>>>> but I can't figure out how to display the lines of the .txt file.

To output the decrypted data you simply would use std::cout instead of outData to display it in a console.

For the encrypted data you may have unprintable characters. Hence you need to output them as hex code

   cout << hex << setw(2) << (unsigned char)s[i] << " ";

where you need to include <iomanip> additionally to <iostream> and <string>-


0
 

Author Comment

by:scuzzo
ID: 24294259
Here is what I've got so far, show me where I'm going wrong and the 500 points are yours.I believe that it is the argc but I've been out too long.

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
const int htlen=5;
const int ascLEn=256;
const int ecryptCode=10;
void print_usage()
{
      cout<<"Usage"<<endl;
      cout<<"      lab12 -e file1 file2  Encrypt file1 and write cyphertext to file2"<<endl;
      cout<<"      lab12 -d file1 file2  Decrypt file1 and write paintext to file 2"<<endl;
      cout<<"      lab12 -h file1 See first five lines of file."<<endl;
      cout<<"      lab12 -t file1 See last five lines of file."<<endl;
      exit(1);
}
int main(int argc, char* argv[])
{
      if (argc != 4)
            print_usage();
            if (strcmp(argv[1], "-e") !=0&&strcmp(argv[1], "-d")!=0)
                  print_usage();
      ifstream inData;
      ofstream outData;
      inData.open(argv[2]);
      outData.open(argv[3]);
      if (inData.fail()||outData.fail())
      {
            cout<<"File open error!"<<endl;
            return 1;
      }
      string s;
      if (strcmp(argv[1], "-e")==0)
      {
            while (!inData.eof())
            {
                  getline(inData, s);
                  for (int i=0;i<s.length();i++)
                        s[i]=char(s[i] + ecryptCode)%ascLEn;
                  outData<<s;
                  if (!inData.eof())
                        outData<<endl;
            }
      }
      else if (strcmp(argv[1], "-d")==0)
      {
            while (!inData.eof())
            {
                  getline(inData, s);
                        for (int i=0;i<s.length();i++)
                              s[i]=char(s[i]+ascLEn-ecryptCode)%ascLEn;
                  outData<<s;
                  if (!inData.eof())
                        outData<<endl;
            }
      }
      else if (strcmp(argv[1], "-h")==0)//switch to see the first five lines of .txt file
      {
            int line = 0;
            while (!inData.eof())
            {
                        getline(inData, s);
                        if (line++ < 5)
                         {
                          std::cout << s << std::endl;
                         }
                  }

      }else
            cout<<"Please make another choice."<<endl;
      
      inData.close();
      outData.close();
      return 0;
      system("pause");
}
0

Featured Post

Active Directory Webinar

We all know we need to protect and secure our privileges, but where to start? Join Experts Exchange and ManageEngine on Tuesday, April 11, 2017 10:00 AM PDT to learn how to track and secure privileged users in Active Directory.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

In our object-oriented world the class is a minimal unit, a brick for constructing our applications. It is an abstraction and we know well how to use it. In well-designed software we are not usually interested in knowing how objects look in memory. …
How to install Selenium IDE and loops for quick automated testing. Get Selenium IDE from http://seleniumhq.org Go to that link and select download selenium in the right hand columnThat will then direct you to their download page.From that page s…
THe viewer will learn how to use NetBeans IDE 8.0 for Windows to perform CRUD operations on a MySql database.
The viewer will learn how to use and create new code templates in NetBeans IDE 8.0 for Windows.

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question