Ai giải thích giúp em với

#include <iostream>
#include <vector>
using namespace std;

void print_pascals_triangle(int rows);
void print_row(vector<int> row_values);

/* main()
   Prints Pascal's triangle
*/
int main() {
    int rows;

    cout << "Pascal's triangle!" << endl;
    do {
        cout << "Enter how many rows to print (at least 0): ";
        cin >> rows;
    } while(rows < 0);

    print_pascals_triangle(rows);

    return 0;
}

/* print_pascals_triangl(rows)
   Prints the first rows of Pascal's triangle, left-aligned.

   rows: number of rows to print
*/
void print_pascals_triangle(int rows) {
    vector<int> row_values; 

    for(int row = 0; row < rows; ++row) {
        // Update for the next row
        vector<int> new_row = row_values;
        new_row.push_back(1); // Last column is always 1

        // Compute the new row from the current row
        for(int c = 1; c < new_row.size()-1; ++c) 
            new_row.at(c) = row_values.at(c-1) + row_values.at(c);

        // Copy updated row back into the original
        row_values = new_row;

        // Print the updated row
        print_row(row_values);
    }
}

/* print_row(row_values)
   Prints a vector<int> as a row of the triangle. 

   row_values: vector<int> of the values to print
*/
void print_row(vector<int> row_values) {
    for(int value : row_values) {
        cout << value << " ";
    }
    cout << endl;
}