function [cost_and_BOM] = cost_BOM_calculation(user_answers);
    
//This function takes the user's answers and calculates the tiny house
//shell cost along with the associated preliminary BOM.

BOM_fix =  []; //delcare variables this time because of future appends;
cost_fix = 0;
BOM_var =  [];
cost_var = 0;


BOM_matrix_fix = [...
    0.1367         960.00      131.20     960.00      131.20; //2x12,      in
    0.0382         8902.81     340.35     9362.34     357.91; //2x4,       in
    0.0467         4501.52     210.07     4891.52     228.27; //2x6,       in
    0.0815         1736.00     141.41     1736.00     141.41; //2x8,       in
    313.0400       1.00        313.04     1.00        313.04; //b. sink,   pc
    4.9900         31.84       158.89     43.75       218.31; //b. tile,   sqft
    0.8858         1221.64     1082.12    1414.52     1252.98;//insul,     sqft
    250.0000       1.00        250.00     1.00        250.00; //counter,   pc
    289.0000       1.00        289.00     1.00        289.00; //k. sink,   pc
    1.0042         228.42      229.37     261.36      262.46; //m. roof,   sqft
    1798.99        1.00        1798.99    1.00        1798.99; //minisplit, pc
    0.3734         2309.51     862.46     2594.36     968.83; //plywood,   sqft
    263.1300       1.00        263.13     1.00        263.13; //q. mat,    pc
    389.0000       1.00        389.00     1.00        389.00; //refrig,    pc
    1.3825         537.19      742.66     610.95      844.64; //shiplap,   sqft
    1.3825         612.32      846.53     693.76      959.12; //siding,    sqft
    555.1700       1.00        555.17     1.00        555.17; //range,     pc
    99.0000        1.00        99.00      1.00        99.00;];//toilet,    pc
    //$ per qty
                   //20ft qty
                               //20ft subtotal
                                         //24ft qty
                                                      //24ft subtotal


if user_answers(1) == 20
    BOM_fix = BOM_matrix_fix(:,2); //take qty's from 20ft model
else
    BOM_fix = BOM_matrix_fix(:,4); //take qty's from 24ft model
end

if user_answers(1) == 20
    cost_fix = sum(BOM_matrix_fix(:,3)); //sum $ from 20ft model
else
    cost_fix = sum(BOM_matrix_fix(:,5)); //sum $ from 24ft model
end


BOM_matrix_var = [...
    6699.0000      1.00        6699.00    0.00        0.00;   //20ft,      pc
    6999.0000      0.00        0.00       1.00        6999.00;//24ft,      pc
    323.4800       1.00        323.48     1.00        323.48; //b. tub,    pc
    59.2100        1.00        59.21      1.00        59.21;  //microwave, pc
    999.0000       1.00        999.00     1.00        999.00; //washing,   pc
    81.2300        6.00        487.38     6.00        487.38; //window,    pc
    0.0382         216.00      8.26       216.00      8.26;]; //wind 2x4,  in
                                                                //based on #14
    //$ per qty
                   //20ft qty
                               //20ft subtotal
                                         //24ft qty
                                                      //24ft subtotal


//Account for trailer chosen:
if user_answers(1) == 20
    BOM_var = [BOM_var; BOM_matrix_var(1,2);];
                    //append qty 1 of 20ft trailer
    cost_var = cost_var + BOM_matrix_var(1,3);
                    //add cost of 20ft trailer

else
    BOM_var = [BOM_var; BOM_matrix_var(2,4);];
                    //append qty 1 of 24ft trailer
    cost_var = cost_var + BOM_matrix_var(2,5);
                    //add cost of 20ft trailer
end


//Acccount for bathtub:
if user_answers(12) == 1
    BOM_var = [BOM_var; 1;];
                    //append qty 1 bathtub
    cost_var = cost_var + BOM_matrix_var(3,1);
                    //add cost of bathtub

else
    BOM_var = [BOM_var; 0;];
                    //append qty 0 bathtub
    //no changes to cost_variable
end


//Acccount for microwave:
if user_answers(8) == 1
    BOM_var = [BOM_var; 1;];
                    //append qty 1 microwave
    cost_var = cost_var + BOM_matrix_var(4,1);
                    //add cost of microwave

else
    BOM_var = [BOM_var; 0;];
                    //append qty 0 microwave
    //no changes to cost_variable
end


//Acccount for washing machine;
if user_answers(9) == 1
    BOM_var = [BOM_var; 1;];
                    //append qty 1 washing machine
    cost_var = cost_var + BOM_matrix_var(5,1);
                    //add cost of washing machine

else
    BOM_var = [BOM_var; 0;];
                    //append qty 0 washing machine
    //no changes to cost_variable
end


//Acccount for windows
if user_answers(14) > 0
    BOM_var = [BOM_var; user_answers(14);];
                    //append input qty of windows
    cost_var = cost_var + BOM_matrix_var(6,1)*user_answers(14);
                    //add cost of all windows

else
    BOM_var = [BOM_var; 0;];
                    //append qty 0 washing machine
    //no changes to cost_variable
end


//Account for extra 2x4s if windows are chosen (ignore reduction in insul)
if user_answers(14) > 0
    BOM_fix(2) = BOM_fix(2) + user_answers(14)*2*18;
        //add 18in of 2x4 (more than necessary) on top and bottom per window
    cost_fix = cost_fix + BOM_matrix_fix(2,1)*2*18*user_answers(14);
        //add cost for 18in of 2x4 on top and bottom per window
end

BOM_final = [BOM_fix; BOM_var;];            //add BOMs together
cost_final = cost_fix + cost_var;           //add costs together

cost_and_BOM = [cost_final; BOM_final;];    //combine into one list


endfunction