Istream& error

Hi,

I am copying the following function from Accelerated C++

Code:

---

istream& read_hw(istream& in, vector<double>& hw)
{
        if(in) {
                hw.clear();

                double x;
                while(in >> x)
                        hw.push_back(x);

                in.clear();
        }
        return in;
}

---

I get the following error:

error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

Anybody know why?

Looking at the book, it doesnt advise that I need to attach a type?

Thanks.

Is this all of the code? There is nothing wrong with the function you posted -- the error is elsewhere.

Check that you included the necessary headers.

Hi,

Thanks for the responses. The error definately points to this function and is the only error within the code.

The header I have included is <iostream>, is that correct?

Thanks.

Which line does the error point to? You need <vector> for vector naturally, but I imagine you've got that too.

Here is the full code and error messages:

Code:

---

#include <iostream>
#include <string>
#include <algorithm>
#include <iomanip>
#include <ios>
#include <vector>



// say what standard-library names we use
using std::cin;
using std::cout;
using std::endl;
using std::string;
using std::max;
using std::setprecision;
using std::sort;
using std::streamsize;
using std::vector;

double median(vector<double> vec)
{
        typedef vector<double>::size_type vec_sz;

        vec_sz size = vec.size();
       

        sort(vec.begin(), vec.end());

        vec_sz mid = size/2;

        return size % 2 == 0 ? (vec[mid] + vec[mid-1]) / 2 : vec[mid];
}

double grade(double midterm, double final, double homework)
{
        return 0.2 * midterm + 0.4 * final + 0.4 * homework;
}

double grade(double midterm, double final, const vector<double>& hw)
{
       
        return grade(midterm, final, median(hw));
}

istream& read_hw(istream& in, vector<double>& hw)
{
        if(in) {
                hw.clear();

                double x;
                while(in >> x)
                        hw.push_back(x);

                in.clear();
        }
        return in;
}



int main()
{
       
        cout << "Please enter your name: ";
        string name;
        cin >> name;
        cout << "Hello " << name << "!" << endl;

        cout << "Please enter your midterm and final exam grades: ";
        double midterm, final;
        cin >> midterm >> final;

        cout << "Enter all your homework grades, "
                "followed by end-of-file: ";

        vector<double> homework;

        read_hw(cin, homework);

       
                double final_grade = grade(midterm, final, homework);

                streamsize prec = cout.precision();
                cout << "Your final grade is " << setprecision(3)
                        << final_grade << setprecision(prec) << endl;
       
        cin.get();
        return 0;
}

---

1>c:\users\darren\documents\visual studio 2008\projects\acceleratedc++\test.cpp(46) : error C2143: syntax error : missing ';' before '&'
1>c:\users\darren\documents\visual studio 2008\projects\acceleratedc++\test.cpp(46) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\users\darren\documents\visual studio 2008\projects\acceleratedc++\test.cpp(46) : error C2065: 'in' : undeclared identifier
1>c:\users\darren\documents\visual studio 2008\projects\acceleratedc++\test.cpp(46) : error C2065: 'hw' : undeclared identifier
1>c:\users\darren\documents\visual studio 2008\projects\acceleratedc++\test.cpp(46) : error C2275: 'std::vector<_Ty>' : illegal use of this type as an expression

As you can see, all errors point to that one line.

Thanks.

You forgot the using declaration for istream.

Ha....so simple!

Thanks. I usually just use namespace std, but i'm wanting to understand that a little more, hence doing it the long way.

Thanks all.