vector function to assign value to an element?

[wolfv]

I am looking for vector function that assigns a value to an element, and if the vector is too short, the vector is extended to the element's position.
I did not find such a function at http://www.cplusplus.com/reference/vector/vector/ but maybe I missed something.

I could use a function something like:

vector::assignElement(unsigned int position, unsigned int val)
{
    if (position >= size())
    {
        this.resize(position+1);
    }
    this.[position] = val;
}

The above function is probably has syntax errors.
Someone must have done this before, seems like there would be many uses for such a function.
How would I find such a vector function?

Thank you.

[gunnerfunner]

http://en.cppreference.com/w/cpp/container/vector/resize

[Peter87]

std::vector doesn't have such a function so you would have to write your own.

[wolfv]

Thanks Peter87.
Here is my assignElement() function in action:

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

struct Map
{
    unsigned int mat=32;
    unsigned int row=32;
    unsigned int col=32;
};

struct Row
{
    std::string scanner;
    std::string pin;
    std::vector<Map> vLayoutToKeyMatrix;
};

struct RowInv
{
    std::vector<Map> vKeyMatrixToLayout;
};

struct Matrix
{
    std::vector<Row> vRows;
    std::vector<RowInv> vRowsInv;
};

void assignElement(std::vector<Map>& vKeyMatrixToLayout, unsigned int position, unsigned int val)
{
    if (position >= vKeyMatrixToLayout.size())
    {
        vKeyMatrixToLayout.resize(position+1);
    }
    vKeyMatrixToLayout[position].col = val;
}

std::vector<Matrix> vMatrices;

void print_vRowsInv()
{
    std::cout << "vRowsInv contains:";
    for (unsigned int i=0;i<vMatrices[0].vRowsInv[0].vKeyMatrixToLayout.size();i++)
    {
        std::cout << " " << vMatrices[0].vRowsInv[0].vKeyMatrixToLayout[i].col;
    }
    std::cout << '\n';
}

int main()
{
    vMatrices.push_back(Matrix());

    //instantiate vRows
    vMatrices[0].vRows.push_back(Row());
    vMatrices[0].vRows[0].vLayoutToKeyMatrix.push_back(Map());

    //instantiate vRowsInv
    vMatrices[0].vRowsInv.push_back(RowInv());
    vMatrices[0].vRowsInv[0].vKeyMatrixToLayout.resize(2);

    //test assignElement()
    print_vRowsInv();
    assignElement(vMatrices[0].vRowsInv[0].vKeyMatrixToLayout, 4, 9);
    print_vRowsInv();
}

output:

vRowsInv contains: 32 32
vRowsInv contains: 32 32 32 32 9