Add 2 Arrays into Vector in specific order c++

Question

Suppose I have 2 string arrays,

string firstName[John, Jane, Jason];
string middleName[L, M, N];

And a vector of strings,

vector<string> vec;

Is there a way to add these to the vector in a specific order so that each middle name is with each first name? So that when I print out the vector, it would print as:

John L

Jane M

Jason N

To add them to the vector I have:

    vector<string> vec;

    string firstName[] ={"John","Jane","Jason"};
    int N = sizeof(firstName)/ sizeof(firstName[0]);

    for(int i=0; i<N;i++)
        p.push_back(firstName[i]);

    string middleName[]={"L","M","N"};
    N = sizeof(middleName)/ sizeof(middleName[0]);

    for(int i=0; i<N;i++)
        p.push_back(middleName[i]);

But obviously that just prints in a single line "John Jane Jason L M N"

Answer 1

Couldn't add a comment due to reputation.
As Johnny Mopp's comment says, the answer is

After ensuring they are the same size: for (int i=0; i < N; i++) p.push_back(firstName[i] + " " + middleName[i]);

To answer the last comment by OP:
You would of course need to know which person's surname it is. If there are n people and m(?n) surnames, and you have the indices of those people who have surnames, then you just need to modify strings in the vector.
For example, if vector p (as above) has a size n, and you have an array LastNamePositions giving the positions of people with surnames, and LastNames stores the last names, then:

for (int i=0; i<LastNamePositions.size(); i++) {
    p[LastNamePositions[i]] = p[LastNamePositions[i]]+" "+LastNames[i];
}