Storing vector in a struct C++

Question

Why can't I do this:

struct sName {
  vector<int> x;
};

It takes only three pointers to store a vector, so I should be able to do this?

Answer 1

#include <vector>

using namespace std;

struct sName {
  vector<int> x;
};

int main()
{
return 0;
}

Compiled with:

g++ -Wall 1.cpp

Compiled fine.

What seems to be the problem with your code?

Answer 2

You can do this. In fact, what you have above is correct and works fine (aside from the missing semicolon and potentially missing std:: in std::vector). Please, rephrase your question so that it doesn't contradict itself.

Answer 3

You mentioned this failed in a switch statement. You'll need to wrap it up in an extra pair of braces:

int type = UNKNOWN;
switch(type)
{
  case UNKNOWN:
    cout << "try again" << endl;
    break;
  case KNOWN:
  { // Note the extra braces here...
    struct sName
    { 
      vector<int> x;
    } myVector; 
  } // and here
}

Alternatively, you could have already declared the structure, and are just trying to declare and initialize a local variable. This isn't a problem unique to struct, it'll happen anytime you try to initialize a variable inside a case:

struct sName
{ 
  vector<int> x;
};

int type = UNKNOWN;
switch(type)
{
  case UNKNOWN:
    cout << "try again" << endl;
    break;
  case KNOWN:
  { // Note the extra braces here...
    sName myVector;
  } // and here
  case OTHER:
    int invalid = 0; // this will also fail without the extra pair of braces
    break;
}

Answer 4

did you forget using namespace std?