Thread: 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.

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.

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.