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What is the arguments in main when we don't pass anything?

Discussion in 'C' started by Bazman, Jul 8, 2010.

  1. Bazman

    Bazman New Member

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    Hi there,

    I am now trialing the code below. It uses arguments supplied to the main function. I have no come across this before?
    When I run the code it just displays :

    usage: PR <filename>

    argc=1 and arv has a sting the tells you the file location.

    So where do the arguments come from?


    Code:
    
    #include <iostream>
    #include<fstream>
    using namespace std;
    
    int main(int argc, char *argv[])
    {
    char ch;
    
    if(argc!=2){
    	cout << "usage: PR <filename>\n";
    	return 1;
    }
    
    ifstream in(argv[1], ios::in |ios::binary);
    if(!in){
    cout << "Cannot open file.\n";
    return 1;
    }
    
    while(in){
    	in.get(ch);
    	if(in) cout << ch;
    }
    
    	in.close();
    
    	return 0;
    }
    
    
     
  2. NewsBot

    NewsBot New Member

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    Normally the running executable is the first param to main and you are only getting that.
     

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