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c++vectorinsert

How do I add elements to an empty vector in a loop?

I am trying to create an empty vector inside a loop, and want to add an element to the vector each time something is read in to that loop.

#include <iostream>
#include <vector>

using namespace std;

int main()
{
   std::vector<float> myVector();

   float x;
   while(cin >> x)
      myVector.insert(x);

   return 0;
}

But this is giving me error messages.

Solution

  • You need to use std::vector::push_back() instead:

    while(cin >> x)
  myVector.push_back(x);
//         ^^^^^^^^^

    and not std::vector::insert(), which, as you can see in the link, needs an iterator to indicate the position where you want to insert the element.

    Also, as what @Joel has commented, you should remove the parentheses in your vector variable's definition.

    std::vector<float> myVector;

    and not

    std::vector<float> myVector();

    By doing the latter, you run into C++'s Most Vexing Parse problem.