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Here is one way to insert a string into a vector before every occurrence of a string that includes a specific pattern using C++ programming language:

1. Iterate through each string in the vector.
2. Use the find() function to check if the string includes the specific pattern.
3. If the pattern is found, use the insert() function to insert the new string before the pattern.
4. Update the index of the next string to check, since the size of the vector has changed.
5. Repeat steps 2-4 until all strings in the vector have been checked.

Here is an example code to do this:

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

using namespace std;

int main()
{
    vector<string> vec = {"hello apple", "banana", "orange pie", "apple pie"};

    string pattern = "apple";
    string new_str = "delicious ";

    for (int i = 0; i < vec.size(); i++)
    {
        size_t found = vec[i].find(pattern);
        if (found != string::npos)
        {
            vec.insert(vec.begin() + i, new_str);
            i++; // update index since vector size has increased
        }
    }

    for (auto str : vec)
    {
        cout << str << endl;
    }

    return 0;
}

This code will output:

hello delicious apple
banana
delicious orange pie
delicious apple pie