The Wall

October 18, 2011

Ray Panko gives this exercise as a test for the accuracy of spreadsheet development; in his tests he found 62 errors in 150 spreadsheet solutions (some spreadsheets contained more than one error), which he finds is typical of spreadsheet users—hopefully professional programmers make fewer errors:

You are to build a spreadsheet model to help you create a bid to build a wall. You will offer two options — lava rock or brick. Both walls will be built by crews of two. Crews will work three 8-hour days to build either type of wall. The wall will be 20 feet long, 6 feet tall, and 2 feet thick. Wages will be $10 per hour. You will have to add 20% to wages to cover fringe benefits. Lava rock will cost $3 per cubic foot. Brick will cost $2 per cubic foot. Your bid must add a profit margin of 30% to your expected cost.

Your task is to write a program that prompts the user for input of the various parameters—wall dimensions, crew days, rock cost, and so on—and prints a neat calculation of the bid price for the wall. When you are finished, you are welcome to read or run a suggested solution, or to post your own solution or discuss the exercise in the comments below.

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2 Responses to “The Wall”

  1. Nick Kimbrough said

    Here is my solution in C++, I’m a beginner so I’m sure there are plenty of mistakes, but pointers would help me out!

    #include “stdafx.h”
    #include

    float MaterialCost(int x)
    {
    using namespace std;
    //This switch compares the choice selected previously by the user and then
    //returns the appropriate price
    switch (x)
    {
    case 1:
    return 2.0;
    break;
    case 2:
    return 3.0;
    break;
    default:
    cout << "Error, closing!";
    cin.get();
    cin.ignore();
    exit (1);
    }
    }

    int main()
    {
    using namespace std;

    //Getting material of wall
    cout << "What will this wall be made of? Make a selection from the list below:\n\n";
    cout << "1. Brick\n";
    cout <> nMaterialType;

    //Setting cost per cubic foot of materials
    float fMaterialCost;
    fMaterialCost = MaterialCost(nMaterialType);

    //Getting height of wall
    cout <> fWallHeight;

    //Getting length of wall
    cout <> fWallLength;

    //Getting Width of wall
    cout <> fWallWidth;

    //Setting total cubic feet of wall
    float fCubicFeet;
    fCubicFeet = fWallLength*fWallHeight*fWallWidth;

    //Get crew number
    cout <> nLaborers;

    //Get crew wages per hour
    cout <> fWagesPerHour;

    //get fringe benifits
    cout <> nFringeBenefits;

    //get days project will take
    cout <> nDays;

    //Calculates desired profit margin
    cout <> nProfitMargin;

    //Calculate total worker cost by taking workers times days times wages then adding benefits on top
    float fTotalWages =((nLaborers*fWagesPerHour)*((float).01*nFringeBenefits+1))*(nDays*8);

    //Calculate total material cost
    float fTotalMaterialCost=(fMaterialCost*fCubicFeet);

    //Calculate final project cost plus profit margin
    float fProjectCost=((fTotalMaterialCost+fTotalWages)*(nProfitMargin*(float).01+1));

    cout << "######################################################\n";
    cout << "#\t\t—–Bid for Wall—–\n";
    cout << "# Materials:\t\t\t\t\t\n";
    cout << "#\tLength in feet:\t\t\t$" << fWallLength << "\n";
    cout << "#\tHeight in feet:\t\t\t$" << fWallHeight << "\n";
    cout << "#\tWidth in feet:\t\t\t$" << fWallWidth << "\n";
    cout << "#\tTotal cubic feet:\t\t$" << fCubicFeet << "\n";
    cout << "#\tCost per cubic foot:\t\t$" << fMaterialCost << "\n";
    cout << "#\tTotal:\t\t\t\t$" << fTotalMaterialCost << "\n";
    cout << "#—————————————————–\n";
    cout << "# Labor\n";
    cout << "#\tCrew Size:\t\t\t$" << nLaborers << endl;
    cout << "#\tDays Worked:\t\t\t$" << nDays << endl;
    cout << "#\tCrew Wages Per Hour:\t\t$" << fWagesPerHour << endl;
    cout << "#\tTotal Wages:\t\t\t$" << fTotalWages/((float).01*nFringeBenefits+1) << endl;
    cout << "#\tFringe benefits:\t\t$" << fTotalWages-(nLaborers*fWagesPerHour) << endl;
    cout << "#\tTotal Labor Cost:\t\t$" << fTotalWages << endl;
    cout << "#—————————————————–\n";
    cout << "# Totals:\n";
    cout << "#\tTotal Cost:\t\t\t$" << fTotalMaterialCost+fTotalWages << endl;
    cout << "#\tMarkup:\t\t\t\t$" << fProjectCost-(fTotalMaterialCost+fTotalWages) << endl;
    cout << "#\n";
    cout << "#\tBid Price:\t\t\t$" << fProjectCost << endl;
    cout << "#—————————————————–\n";
    cout << "######################################################";
    cin.get();
    cin.ignore();
    return 0;
    }

  2. Joe said

    I can’t believe I “forgot” to read your blog considering that I found it three months earlier. Also busy with do the job I guess. Anyways I have it bookmarked now to become confident that I get notified as soon as you put some new content up.

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