การบ้านครั้งที่ 6

5.3

using System;

namespace Calculateinterest

{

class Program

{

static void Main()

{

Console.Write("Enter principal:");

string sPrincipal = Console.ReadLine();

decimal mPrincipal = Convert.ToDecimal(sPrincipal);

if (mPrincipal < 0)

{

Console.WriteLine("Principal cannot be negative");

mPrincipal = 0;

}

Console.Write("Enter interest: ");

string sinterest = Console.ReadLine();

decimal minterest = Convert.ToDecimal(sinterest);

if (minterest < 0)

{

Console.WriteLine("Interest cannot be negative");

minterest = 0;

}

decimal mInterestPaid;

mInterestPaid = mPrincipal * (minterest / 100);

decimal mTotal = mPrincipal + mInterestPaid;

Console.WriteLine();

Console.WriteLine("Principal = " + mPrincipal);

Console.WriteLine("Interest = " + minterest + "%");

Console.WriteLine();

Console.WriteLine("Interest paid = " + mInterestPaid);

Console.WriteLine("Total = " + mTotal);

Console.WriteLine("Press Enter to terminate...");

Console.Read();

}

}

}

5.13
using System;

namespace CalculateInterestTableMoreForgiving

{

class Program

{

static void Main(string[] args)

{

int nMaximumInterest = 50;

decimal mPrincipal;

while(true)

{

Console.Write("Enter principal : ");

string sPrincipal = Console.ReadLine();

mPrincipal = Convert.ToDecimal(sPrincipal);

if(mPrincipal >= 0)

{

break;

}

Console.WriteLine("Principal cannot be negatine");

Console.WriteLine("Try again");

Console.WriteLine();

decimal mInterest;

while(true)

{

Console.Write("Enter interest: ");

string sInterest = Console.ReadLine();

mInterest = Convert.ToDecimal(sInterest);

if (mInterest >= 0 && mInterest <= nMaximumInterest)

{

break;

}

Console.WriteLine("Interest

Console.WriteLine();

}

Console.Write("Enter number of years:");

string sDuration = Console.ReadLine();cannot be nagative" +

"or greater than " + nMaximumInterest);

Console.WriteLine("Try again");

int nDuration = Convert.ToInt32(sDuration);

Console.WriteLine();

Console.WriteLine("Principal = " + mPrincipal);

Console.WriteLine("Interest = " + minteresr + "%");

Console.WriteLine("Duration = " + nDuration + "years");

Console.WriteLine();

int nYear = 1;

while (nYear <= nDuration)

{

decimal mInterestPaid;

mInterestPaid = mPrincipal * (mInterest / 100);

mPrincipal = mPrincipal + mInterestPaid;

mPrincipal =
decimal.Round(mPrincipal, 2);

Console.WriteLine(nYear + " - " + mPrincipal);

nYear = nYear + 1;

}

Console.WriteLine("Press Enter to terminate...");

Console.Read();

}

}

}

7.7
using System;

namespace Studentname

{

class Student

{

private int idNumber;

private string lastname;

private double gradePointAverage;

public int getld()

{

return idNumber;

}

public string getName()

{

return lastname;

}

public double getGPA()

{

return gradePointAverage;

}

public void setld(int id)

{

idNumber = id;

}

public void setName(string name)

{

lastname = name;

}

public void setGPA(double gpa)

{

gradePointAverage = gpa;

}

}

class Program

{

static void Main()

{

Student st =
new Student();

st.setld(9353);

st.setName(
"Teerawat");

st.setGPA(3.98);

Console.WriteLine("Student name {0} has ID # {1} and gpa of {2}",

st.getName(), st.getld(), st.getGPA());

Console.ReadLine();

}

}

}

8.6
using System;

using System.Windows.Froms;

namespace UsePredefineMethods

{

static class Program

{

static void Main()

{

double[] waterDepth = { 45, 19, 2, 16.8, 190, 0.8, 510, 6, 18 };

string outputMsg = "";

string caption = "System.Array Methods lllustrated";

double[] w = new double[20];

outputMsg += "waterDepth Array\n\n";

foreach (double wVal in waterDepth)

outputMsg += "\n";

MessageBox.Show(outputMsg, caption);

Array.Copy(waterDepth, 2, w, 0, 5);

Array.Sort(w);

outputMsg = "Array w Sorted\n\n";

foreach (double wVal in w)

{

if (wVal > 0)

outputMsg += wVal + "\n";

}

MessageBox.Show(outputMsg, caption);

Array.Reverse(w);

outputMsg = "Array w Reverse\n\n";

foreach (double wVal in w)

{

if (wVal > 0)

outputMsg += wVal + "\n";

}

MessageBox.Show(outputMsg, caption);

}

}

}