Why won't my project include vectors or arrays?

Question

So I'm still learning C++ and I can't figure out what I am doing wrong. I am using the Code::Blocks IDE and despite including the vector and array header it gives me a big list of errors and says nothing was declared in this scope. The code is very basic:

#include <iostream>
#include <vector>
#include <array>
#include <string>

using namespace std;

int main()
{
string b = const, 10;
vector<string> string1(b);
array<string, b> string2;
return 0;
}

Ok, for the record, THIS IS WHAT I WAS TRYING TO DO:

"Declare a vector object of 10 string objects and an array object of 10 string objects. Show the necessary header files and don’t use using. Do use a const for the number of strings."

`string b = const, 10;` -- What exactly do you expect that line to do? — Benjamin Lindley, Apr 28 '14 at 23:51
The only line of code in `main` that makes any sense is `return 0;` — Ed S., Apr 28 '14 at 23:59
I suggest you pick up a [spectacular book on C++](http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list) and take a look at a glorious [online C++ reference](http://en.cppreference.com/w/cpp). — Captain Obvlious, Apr 29 '14 at 00:03
There are many, many examples of how to use these classes. Please find some and study them. — chris, Apr 29 '14 at 00:03
That big list of errors is pointing you in the right direction. Captain Obvlious's linked online reference should help out with most of what you run into as you're learning basic usage of STL. — randomusername, Apr 29 '14 at 00:14
Guess you took "do use a const for the number of strings" too literally — Lightness Races in Orbit, Apr 29 '14 at 08:41

Ed S. · Answer 1 · 2014-04-29T02:36:17.933

You errors are, line by line...

string b = const, 10;

That one simply makes no sense, I don't know what you were expecting there. Assign a string to b instead.

string b = "whatever";

vector<string> string1(b);

vector<T> contains no constructor that takes a T. In your case, no constructor which takes a string. If your compiler supports it, you could use:

vector<string> string1 = {b};

If it doesn't, easy enough to just...

vector<string> string1;
string1.push_back(b);

array<string, b> string2;

array<T,size_t> takes a T (string) and the number of elements, a size_t, as its template arguments. b is a string, not a size_t, so this makes no sense. Pass the size as the second template argument.

array<string, 10> string2;

Per @Benjamin Lindley's comment, perhaps you meant to declare a const int with a value of 10 in that first line. If so, then...

int main()
{
    const int b = 10;
    vector<string> string1(b);
    array<string, b> string2;
    return 0;
}

I think perhaps the intent of the first line was to declare a `const` integer to use for the size of both the vector and the array. That would mean that the only thing that needs to be corrected is the first line. I have no idea how `string` got in there though. — Benjamin Lindley, Apr 29 '14 at 00:18

Why won't my project include vectors or arrays?

1 Answers1