Array of sets

How to implement array of sets? is there anyway I can do it dynamically, just at the running time I wont be able to know how many sets I need but as I create a set i want to save it and then compare it for my purpose, the question is:

How Can i create sets at the run time without wasting memory, and How can I track them again.

Perhaps you can use a std::vector<std::set<T> >

Why this declaration is not working?

Code:

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        vector <set> s;

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Quote:

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Originally Posted by kapil1089thekin

Why this declaration is not working?

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Maybe the appropriate using declarations (using std::vector; using std::set) or using directive (using namespace std; ) are/is not in scope.

I have used

Code:

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using namespace std;

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And I feel its in the scope, tomake it more clear I posting the error.

Code:

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rectangle.cpp:230: error: type/value mismatch at argument 1 in template parameter list for ‘template<class _Tp, class _Alloc> class std::vector’
rectangle.cpp:230: error:  expected a type, got ‘set’
rectangle.cpp:230: error: template argument 2 is invalid
rectangle.cpp:230: error: invalid type in declaration before ‘;’ token

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Post the smallest and simplest program that you expect to compile but which demonstrates the error.

Code:

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#include <iostream>
#include <vector>
#include <set>
using namespace std;

int main()
{
        vector<set> vector_set
        return 0;
}

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The set must be a set of something, e.g., a set of ints:

Code:

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#include <iostream>
#include <vector>
#include <set>
using namespace std;

int main()
{
        vector<set<int> > vector_set;
        return 0;
}

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Code:

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#include <iostream>
#include <vector>
#include <set>
using namespace std;
void add123(vector<set<int> >& numbers);

int main()
{
        vector<set<int> > vector_set;
        add123(vector_set);
        //cout << vector_set[0]; //how to print/access the 1st element of the first set of the vector vector_set?
        return 0;
}
void add123(vector<set<int> >& numbers)
{
        set<int> s;
        s.insert(123);
        numbers.push_back(s);
}

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Perhaps

Code:

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#include <iostream>
#include <vector>
#include <set>
using namespace std;
void add123(vector<set<int> >& numbers);

int main()
{
        vector<set<int> > vector_set;
        add123(vector_set);
        cout << *vector_set[0].begin();
        return 0;
}
void add123(vector<set<int> >& numbers)
{
        set<int> s;
        s.insert(123);
        numbers.push_back(s);
}

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