Passing command line arguments

Question

Okay I have updated my code a little, but I am still not exactly sure how to use the vector of command line arguments that I pass. I tried to set it up like the code I have below, but it wont compile. It gives me the error that it cannot find argc and argv:

1>c:\users\chris\documents\visual studio 2008\projects\cplusplustwo\cplusplustwo\application.h(32) : error C2065: 'argc' : undeclared identifier 1>c:\users\chris\documents\visual studio 2008\projects\cplusplustwo\cplusplustwo\application.h(32) : error C2065: 'argv' : undeclared identifier

main.cpp

#include "application.h"

int main(int argc,char *argv[]){
    vector<string> args(argv, argv + argc);
    return app.run(args);    
}

application.h

#include <boost/regex.hpp>
#include <iostream>
#include <string>
#include <fstream>
#include <sstream>
#include "time.h"
using namespace std;



class application{
private:
    //Variables
    boost::regex expression;
    string line;
    string pat;
    string replace;
    int lineNumber;
    char date[9];
    char time[9];


    void commandLine(vector<string> args){
        string  expression="";    // Expression
        string  textReplace="";   // Replacement Text
        string  inputFile="";     // Input File
        string  outputFile="";    // Output Directory
        int optind=1;
        // decode arguments
        for(vector<string>::iterator i = args.begin(); i != args.end(); ++i){
            while ((optind < argc) && (argv[optind][0]=='-')) {
                string sw = argv[optind];
                if (*i == "-e") {
                    optind++;
                    expression = argv[optind];
                }
                else if (*i == "-t") {
                    optind++;
                    textReplace = argv[optind];
                }
                else if (*i == "-i") {
                    optind++;
                    inputFile = argv[optind];
                }
                else if (*i == "-o") {
                    optind++;
                    outputFile = argv[optind];
                }
                else{
                    cout << "Unknown switch: " 
                        << argv[optind] << "Please enter one of the correct parameters:\n" 
                        << "-e + \"expression\"\n-t + \"replacement Text\"\n-i + \"Input File\"\n-o + \"Onput File\"\n";
                    optind++;
                }
            }
        }
    }
    //Functions
    void getExpression(){
        cout << "Expression: ";
        getline(cin,pat);
        try{
            expression = pat;
        }
        catch(boost::bad_expression){
            cout << pat << " is not a valid regular expression\n";
            exit(1);
        }
    }

    void boostMatch(){
        //Define replace {FOR TESTING PURPOSES ONLY!!! REMOVE BEFORE SUBMITTING!!
        replace = "";
        _strdate_s(date);
        _strtime_s(time);
        lineNumber = 0;
        //Files to open
        //Input Files
        ifstream in("files/trff292010.csv");
            if(!in) cerr << "no file\n";
        //Output Files
        ofstream newFile("files/NEWtrff292010.csv");
        ofstream copy("files/ORIGtrff292010.csv");
        ofstream report("files/REPORT.dat", ios.app);
        lineNumber++;
        while(getline(in,line)){
            lineNumber++;
            boost::smatch matches;
            copy << line << '\n';
            if (regex_search(line, matches, expression)){
                for (int i = 0; i<matches.size(); ++i){
                    report << "Time: " << time << "Date: " << date << '\n'
                        << "Line " << lineNumber <<": " << line << '\n';
                    newFile << boost::regex_replace(line, expression, replace) << "\n";

                }
            }else{
                newFile << line << '\n';
            }
        }
    }

public:
    void run(vector<string> args){
        commandLine(vector<string> args);
        getExpression();
        boostMatch();
    }
};

ORIGINAL POST

I want to pass command line arguments out of main. This is homework for an advanced C++ class. I need to pass the command line with a vector and I am not sure if I am doing everything correctly. Would I pass it into a vector like I did? Also is there a copy() command you can use to copy the command line arguments into a vector rather than pushback?

main.cpp

#include "application.h"

int main(int argc,char *argv[]){
    vector<string> args;
    application app;
    for (int i=1;i<argc;i++){
        args.push_back(argv[i]);
    }
    app.run(args);
    return(0);
}

application.h

#include <boost/regex.hpp>
    #include <iostream>
    #include <string>
    #include <fstream>
    #include <sstream>
    #include "time.h"
    using namespace std;

class application{
private:
    //Variables
    boost::regex expression;
    string line;
    string pat;
    string replace;
    int lineNumber;
    char date[9];
    char time[9];


    void commandLine(vector<string> args){
        string  expression="";    // Expression
        string  textReplace="";   // Replacement Text
        string  inputFile="";     // Input File
        string  outputFile="";    // Output Directory
        int optind=1;
        // decode arguments
        for(vector<string>::iterator i = args.begin(); i != args.end(); ++i){
            while ((optind < argc) && (argv[optind][0]=='-')) {
                string sw = argv[optind];
                if (*i == "-e") {
                    optind++;
                    expression = argv[optind];
                }
                else if (*i == "-t") {
                    optind++;
                    textReplace = argv[optind];
                }
                else if (*i == "-i") {
                    optind++;
                    inputFile = argv[optind];
                }
                else if (*i == "-o") {
                    optind++;
                    outputFile = argv[optind];
                }
                else{
                    cout << "Unknown switch: " 
                        << argv[optind] << "Please enter one of the correct parameters:\n" 
                        << "-e + \"expression\"\n-t + \"replacement Text\"\n-i + \"Input File\"\n-o + \"Onput File\"\n";
                    optind++;
                }
            }
        }
    }
    //Functions
    void getExpression(){
        cout << "Expression: ";
        getline(cin,pat);
        try{
            expression = pat;
        }
        catch(boost::bad_expression){
            cout << pat << " is not a valid regular expression\n";
            exit(1);
        }
    }

    void boostMatch(){
        //Define replace {FOR TESTING PURPOSES ONLY!!! REMOVE BEFORE SUBMITTING!!
        replace = "";
        _strdate_s(date);
        _strtime_s(time);
        lineNumber = 0;
        //Files to open
        //Input Files
        ifstream in("files/trff292010.csv");
            if(!in) cerr << "no file\n";
        //Output Files
        ofstream newFile("files/NEWtrff292010.csv");
        ofstream copy("files/ORIGtrff292010.csv");
        ofstream report("files/REPORT.dat", ios.app);
        lineNumber++;
        while(getline(in,line)){
            lineNumber++;
            boost::smatch matches;
            copy << line << '\n';
            if (regex_search(line, matches, expression)){
                for (int i = 0; i<matches.size(); ++i){
                    report << "Time: " << time << "Date: " << date << '\n'
                        << "Line " << lineNumber <<": " << line << '\n';
                    newFile << boost::regex_replace(line, expression, replace) << "\n";

                }
            }else{
                newFile << line << '\n';
            }
        }
    }

public:
    void run(vector<string> args){
        commandLine(vector<string> args);
        getExpression();
        boostMatch();
    }
};

Answer 1

I'd just write:

vector<string> args(argv + 1, argv + argc + !argc);

This will exclude argv[0], but in a way that's robust even if argc == 0 (possible under Linux, and maybe other OSs too).