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Help with Files and I/O Streams

Discussion in 'C++' started by golf_girl32, Oct 12, 2010.

  1. golf_girl32

    golf_girl32 New Member

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    I need help with this program. I know the file is opening but I'm not sure how to edit the numbers and stuff that is in the file. This is what I have so far.

    Code:
    #include <fstream>
    #include <iostream>
    #include <cstdlib>
    
    int main()
    {
        using namespace std;
        ifstream input;
        ofstream output;
    
        input.open("input.txt");
        if (input.fail())
        {
            cout<<"Input file opening failed.\n";
            exit(1);
        }
    
        output.open("grade.txt");
        if (output.fail())
        {
            cout<<"Output file opening failed.\n";
            exit(1);
        }
    
        input.close();
        output.close();
    
        return 0;
    }
    
    
     
  2. virxen

    virxen New Member

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    send the txt file --->input.txt
     
  3. xpi0t0s

    xpi0t0s Mentor

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    If you want to read data from input.txt into variable 'v' and write it out to grade.txt, use:
    Code:
    input >> v;
    output << v;
    
    For multiple variables just use the same as you would for cin/cout, i.e.:
    Code:
    input >> v1 >> v2 >> v3;
    output << v1 << v2 << v3; // may need to add spaces ...<<v1<<" "<<v2...
    
     

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