I'm trying to use a vector of strings in my code instead of an array of strings but apparently I miss some detail in the declaration of the vector. Using the following code, I get this error: ‘vector’ was not declared in this scope
// Try to implement a vector of string elements
#include<iostream>
using namespace std;
int main() {
const int MAX_ITEMS = 10;
vector<string> my_vector(MAX_ITEMS);
return 0;
}
How should I correctly declare the vector?
You should add these includes:
#include <vector>
#include <string>
You have to include the header:
#include <vector>
#include <string>
You need:
#include <vector>
Related
my question is pretty simple but I can't seem to find it out.
I want to know what libary to include when using stoi. I was using atoi and it works fine with
#include <iostream>
#include <string>
#include <stdlib.h>
using namespace std;
but I get "stoi not declared" when I run with stoi. Thanks
You need to #include <string> and use a compiler that understands C++11. Minimal example:
#include <string>
#include <cassert>
int main()
{
std::string example = "1234";
int i = std::stoi(example);
assert(i == 1234);
return 0;
}
Compile, for example, with g++ -std=c++11.
When I run this code I get "invalid template arguments" error on the last line. Please advise. (I've omitted the rest of the code)
#include <iostream>
#include <fstream>
#include<array>
#include <vector>;
using namespace std;
int fileLineCount(string);
int fileExists(string[],int);
int main() {
ifstream archiveFile;
archiveFile.open("StudentRecords.txt");
int lineCount=fileLineCount("StudentRecords.txt");
string line;
vector<string> recordArray;
#include <vector>;
should be
#include <vector>
and of course you need to close the } brace at the end of main() (although probably this was a typo). You should also #include <string>, although some of your headers seem to include it implicitly (probably <iostream>).
I want to define a struct in a flex program :
%{
#include <math.h>
#include <string>
#include <vector>
#include <iostream>
#include <map>
struct Node{
string action;
vector<Node> vecini[];
};
%}
and even though I include vector and string I still get this errors:
error: ‘string’ does not name a type
error: field ‘vecini’ has incomplete type
Thank you !
Both vector and string are in the std namespace so you should add it to the declaration of member variables of those types. Change the code to:
%{
#include <math.h>
#include <string>
#include <vector>
#include <iostream>
#include <map>
struct Node{
std::string action;
std::vector<Node*> vecini[];
};
%}
EDIT: (thanks to Kerrek SB): also you can not define a vector of Node as a member of Node. Instead use a vector of pointers to node like so: std::vector<Node*> vecini[];
Use fully qualified names for string and vector, for example:
std::string action;
^^^^^^^^^^^
Note that, string and vector are defined only in the std namespace, so you need to specify the fully qualified name to tell the compiler under which namespace to find them.
main.cpp
#include <vector>
#include <iostream>
#include "normal.h"
using namespace std;
int main()
{
return 0;
}
normal.h
#ifndef NORMAL_H
#define NORMAL_H
#include <vector>
#include <iostream>
using namespace std;
vector < int > myvector;
myvector.push_back(12);//does not name a type
#endif
I know I need to somehow include vector<int> myvector in main.cpp but can't figure the way. I've looked at my previous programs and didn't need to include anything in main.cpp.
The problem is that the code
myvector.push_back(12); is not inside any function. Outside of functions you may only declare (and possibly initialize) variables, you cannot put other code.
So, even though you can declare your vector in the .h file (probably to have it available in many files) you should move this line inside the main() or some other function.
Like this question already asked, I'd like to initialize a container using STL where the elements are hard-coded in the cleanest manner possible. In this case, the elements are a doubly nested container:
set<vector<int> > A;
And I'd like (for example) to put the following values in:
A = [[0,0,1],[0,1,0],[1,0,0],[0,0,0]];
C++0x fine, using g++ 4.4.1. STL is preferable as I don't use Boost for any other parts of the code (though I wouldn't mind an example with it!).
This does use g++ 4.4.1, with -std=c++0x
#include <set>
#include <vector>
using namespace std;
int main()
{
set<vector<int>> A = {{0,0,1},{0,1,0},{1,0,0},{0,0,0}};
}
#include <boost/assign/list_of.hpp>
#include <vector>
#include <set>
using namespace std;
using namespace boost::assign;
int main()
{
set<vector<int> > A;
A = list_of
(list_of(0)(0)(1))
(list_of(0)(1)(0))
(list_of(1)(0)(0));
(list_of(0)(0)(0));
return 0;
}