vectors and arithmetic progression

[vix290788]

Hi, I have been attempting a question for hours now and don't seem to be getting anywhere. I have to return a vector of <long> containing the arithmetic progression up to N terms, with a and d long arguments, so
a_n = a+n*d

I have created the function vector<long>arith_prog(long, long, int) like follows:

vector<long> arith_prog(long a, long d, int N)
{
vector<long>arith_vec;
long x = 0;
for( int i = 0; i < N; i++)
{
x = a + i*d;
arith_vec.push_back;
x = arith_vec[i];
}
return arith_vec;
}

Can anyone tell me where I am going wrong?
Quick reply would be great!
Thanks

[boxfish]

arith_vec.push_back;
x = arith_vec[i];

You have to pass an argument to push_back. Maybe you meant to push x into the vector?

arith_vec.push_back(x);

By the way, it would be helpful if you used code tags around your code. Put [CODE] before the code and [/CODE] after it, so it shows up in a code box and the indentation isn't wrecked. Thanks.
Hope this helps.

[vix290788]

Thanks, but no unfortunately that still doesn't make it work. I realised this mistake just after I had posted my original message. So can anyone help me as to whats wrong. I get loads of error messages when I try to compile it, which I have no idea what they mean.

vector<long> arith_prog(long a, long d, int N)
    {
    vector<long>arith_vec;
    long x = 0;
    for( int i = 0; i < N; i++)
        {
        x = a + i*d;
        arith_vec.push_back(x);
        x = arith_vec[i];
        }
    return arith_vec;
    }
 

[boxfish]

Please post the error messages here so it's easier for people to help you.
Thanks.
Edit:
I have put your function in a program that calls it, and it works fine. The errors must be from something else. Maybe you forgot to include vector.
This line of code

x = arith_vec[i];

is unnecessary. x is already equal to arith_vec[i], and at that point in your loop it doesn't matter what x equals anyway.

[weaknessforcats]

Did you #include <vector> ??

[vmpstr]

and are you using namespace std?