Thread: Finding common values in the rows of a vector [Need Help]

Can somebody give me a hand with this? I'm doing this for a an application that would print of LCM and GCD (lowest common factor and greatest common divisor) with steps.

I need to get the common factors so I can highlight them when I'm printing them under factors. I tried googling but I could only find programs that would directly find LCM or GCD. It's important I have all the factors.

The best I could come up with:

Code:

int main() {
    vector <float> operands = { 9, 9, 4 };
    vector < vector <float> > factors;
    vector < vector <float> > factors_temp;
    vector <float> common_factors;

    for (const auto& x : operands)
        factors.push_back(prime_factors(x)); // returns a vector 
    
    factors_temp = factors;

    for (unsigned int i = 0; i < factors_temp.size(); i++) {
        for (unsigned int j = 0; j < factors_temp[i].size(); j++) {

            for (unsigned int k = 0; k < factors_temp.size(); k++) {
                for (unsigned int l = 0; l < factors_temp[k].size(); l++) {
                    if (k == i)
                        continue;

                    if (factors_temp[i][j] == factors_temp[k][l]) {
                        common_factors.push_back(factors_temp[i][j]);
                        factors_temp[i].erase(factors_temp[i].begin() + j);
                        factors_temp[k].erase(factors_temp[k].begin() + l);
                    }
                }
            }
        }
    }

    for (const auto& x : common_factors)
        cout << x << "\t";

    cin.get();
    return 0;
}

The logic is completely faulty though. It occasionally works for two operands.

Oh and also I need to erase common factors from the rows and columns themselves. (So they won't repeat while printing out, unless there is a better logic to this)

Thanks for reading, cheers!


here's the other part of the code:

Code:

#include <iostream>
#include <vector>
#include <string>
#include <Windows.h>

using namespace std;

void SetColor(int ForgC) // source: https://stackoverflow.com/questions/29574849/how-to-change-text-color-and-console-color-in-codeblocks
{
    WORD wColor;

    HANDLE hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
    CONSOLE_SCREEN_BUFFER_INFO csbi;

    //We use csbi for the wAttributes word.
    if (GetConsoleScreenBufferInfo(hStdOut, &csbi))
    {
        //Mask out all but the background attribute, and add in the forgournd     color
        wColor = (csbi.wAttributes & 0xF0) + (ForgC & 0x0F);
        SetConsoleTextAttribute(hStdOut, wColor);
    }
    return;
}

vector <int> prime_factors(int number) {  // over-loaded function
    vector <int> prime_factors = { 1 };

    for (int i = 2; i <= number; i++) {
        while (number % i == 0) {
            number /= i;
            prime_factors.push_back(i);
        }
    }
    return prime_factors;
}