CODEWITHSUNDEEP
c++c++11iostream
Jake quin
Jake quin

Reputation: 742

C++: Error on ostream << operator

I don't understand why this code gives me error

void printSalesFile(vector< vector<float> > & list)
{
    ofstream outfile;
    outfile.open("sales.lst", ios::out);
    if (outfile.is_open())
    {
        outfile << setw(6) << right << "ID"
                << setw(12) << "January"
                << setw(12) << "Febuary"
                << setw(12) << "March"
                << setw(12) << "April"
                << setw(12) << "May"
                << setw(12) << "June"
                << setw(12) << "July"
                << setw(12) << "August"
                << setw(12) << "September"
                << setw(12) << "October"
                << setw(12) << "November"
                << setw(12) << "December" << endl;

        for (unsigned int i = 0; i <= list.size(); i++)
        {
            outfile << setw(6) << right << list[i]; //i don't understand why it says there's an error here.
            for(int j = 0; j <= 11; j++)
                outfile << setw(12) << right << list[i][j];
            outfile << endl;
        }
    }
    outfile.close();
}

I have tried deleting it and pasting the things I wrote above that works but still get the errors.

Here is the error message:

   D:\QT\Salesperson\main.cpp:295: error: cannot bind 'std::basic_ostream<char>' lvalue to 'std::basic_ostream<char>&&'
         outfile << setw(6) << list[i];
                ^

As for the text file, it has 2 lines, 1 for the header and another that has values all set to 0

Upvotes: 1

Views: 184

Answers (3)

Jake quin
Jake quin

Reputation: 742

Thank you very much for pointing out the mistakes in my code, forgive me since im only starting out.

for (unsigned int i=0; i<list.size();i++)
{
    outfile<<setw(6)<<right<<list[i][0];
    for(int j = 1; j<13; j++)
        outfile<<setw(12)<<right<<list[i][j];
    outfile<<endl;
}

i have taken the mistakes that everybody pointed out and changed part of the code into this one.It now works thank you very much!

what threw me off was the error pointing to << which made me not look how on list was incorrectly written.

Upvotes: 0

Pete Becker
Pete Becker

Reputation: 76235

outfile<<setw(6)<<right<<list[i]; //i don't understand why it says there's an error here.

It's because there's no stream inserter for std::vector<float>.

Note also that for(unsigned int i = 0; i <= list.size(); ++i) will run off the end of the list. Use < instead of <=.

Upvotes: 3

Fantastic Mr Fox
Fantastic Mr Fox

Reputation: 33854

Since you are using namespace std don't declare list as an object it is likley that you are shadowing this class name. Or better yet, dont use using namespace std because of this problem.

But your problems wont stop there, look at this line:

outfile<<setw(6)<<right<<list[i];

list is a vector< vector<float> > so list[i] will resolve to a vector<float>, how do you print that?

In this line:

for (unsigned int i=0; i<=list.size();i++)

should be i < list.size(), what happens when i == list.size(), you are going to reference vector[vector.size()] which will invoke undefined behaviour (remember that array referencing starts at 0).

There may be other things as well.

Upvotes: 2

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