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Collecting multiple Variables from one loop

I'm Working on a project for college and have sat here trying to figure out a solution to this problem for a solid 3 hours now. the problem is:
Scenario:
You want to calculate a student’s GPA (Grade Point Average) for a number of classes taken by the student during a single semester.
Inputs:
The student’s name.
Class names for the classes taken by the student.
Class letter grade for the classes taken by the student.
Class credit hours for the classes taken by the student.
Processing:
Accept and process classes until the user indicates they are finished.
Accumulate the number of credit hours taken by the student.
Calculate the total number of “points” earned by the student as:
a. For each class calculate the points by multiplying the credit hours for that class times the numeric equivalent of the letter grade. (A=4.0, B=3.0, C=2.0, D=1.0, F=0)
b. Total all points for all classes.
Calculate the GPA as the total number of “points” divided by the total credit hours.
Output:
Display a nicely worded message that includes the student’s name and the GPA (decimal point number with 2 decimal places) achieved by the student that semester.
What I currently have is:
static void Main(string[] args)
{
String StudentName;
//Error Trapping
try
{
Console.WriteLine("Welcome to The GPA Calculator");
Console.WriteLine("Hit any key to continue...");
Console.ReadKey();
Console.Write("Please enter your name: ");
StudentName = Convert.ToString(Console.ReadLine());
InputGradeInfo();
}
//Error Repsonse
catch (System.Exception e)
{
Console.WriteLine("An error has Occurred");
Console.WriteLine("The error was: {0}" , e.Message);
//Belittle the User
Console.WriteLine("Good Job, you Broke it.");
Console.ReadLine();
}
}
public static double InputGradeInfo()
{
String ClassName;
Char LetterGrade;
Double LetterGradeValue;
Double CreditHours;
Double ValueOfClass;
Console.Write("Please enter the class title: ");
ClassName = Convert.ToString(Console.ReadLine());
Console.Write("Please enter the total credits this class is worth: ");
CreditHours = Convert.ToDouble(Console.ReadLine());
Console.Write("Please enter the grade letter recived: ");
LetterGrade = Convert.ToChar(Console.ReadLine());
switch (LetterGrade)
{
case 'a': LetterGradeValue = 4;
break;
case 'A': LetterGradeValue = 4;
break;
case 'b': LetterGradeValue = 3;
break;
case 'B': LetterGradeValue = 3;
break;
case 'c': LetterGradeValue = 2;
break;
case 'C': LetterGradeValue = 2;
break;
case 'd': LetterGradeValue = 1;
break;
case 'D': LetterGradeValue = 1;
break;
case 'f': LetterGradeValue = 0;
break;
case 'F': LetterGradeValue = 0;
break;
default: LetterGradeValue = 0;
break;
}
ValueOfClass = CalculateClass(LetterGradeValue, CreditHours);
return ValueOfClass;
}
public static double CalculateClass(double LetterGrade, double CreditHours)
{
Double CreditTotal;
CreditTotal = CreditHours * LetterGrade;
return CreditTotal;
}
The Problem arises for me as to how one would loop info collection, save it to different variable every time and then breaking the loop using user input at the end. We haven't learned about arrays yet so that's off the table. After I have that looped collection down calculating the total GPA and displaying wouldn't be difficult.
Also I haven't learned about created classes yet so I can't use those either

static void Main(string[] args)
{
String StudentName;
//Error Trapping
try
{
Console.WriteLine("Welcome to The GPA Calculator");
Console.WriteLine("Hit any key to continue...");
Console.ReadKey();
Console.Write("Please enter your name: ");
StudentName = Convert.ToString(Console.ReadLine());
List<double> gradeInfoList = new List<double>();
List<double> creditList = new List<double>();
bool brakeLoop = false;
while (!brakeLoop)
{
gradeInfoList.Add(InputGradeInfo(creditList));
Console.WriteLine("Do you want to continue(y/n): ");
brakeLoop = Console.ReadLine() != "y";
}
Console.WriteLine(StudentName + " GPA is: " + gradeInfoList.Sum() / creditList.Sum());
}
//Error Repsonse
catch (System.Exception e)
{
Console.WriteLine("An error has Occurred");
Console.WriteLine("The error was: {0}", e.Message);
//Belittle the User
Console.WriteLine("Good Job, you Broke it.");
Console.ReadLine();
}
}
public static double InputGradeInfo(List<double> creditList)
{
String ClassName;
Char LetterGrade;
Double LetterGradeValue;
Double CreditHours;
Double ValueOfClass;
Console.Write("Please enter the class title: ");
ClassName = Convert.ToString(Console.ReadLine());
Console.Write("Please enter the total credits this class is worth: ");
CreditHours = Convert.ToDouble(Console.ReadLine());
creditList.Add(CreditHours);
Console.Write("Please enter the grade letter recived: ");
LetterGrade = Convert.ToChar(Console.ReadLine().ToUpper());
switch (LetterGrade)
{
case 'A': LetterGradeValue = 4;
break;
case 'B': LetterGradeValue = 3;
break;
case 'C': LetterGradeValue = 2;
break;
case 'D': LetterGradeValue = 1;
break;
case 'F': LetterGradeValue = 0;
break;
default: LetterGradeValue = 0;
break;
}
ValueOfClass = CalculateClass(LetterGradeValue, CreditHours);
return ValueOfClass;
}
public static double CalculateClass(double LetterGrade, double CreditHours)
{
Double CreditTotal;
CreditTotal = CreditHours * LetterGrade;
return CreditTotal;
}
Here you probably want this. You need one while loop to take all the classes, the loop brakes if you say that you don't want to continue or put another input. You make the gradeInfoList with gradeInfoList.Sum() function.
Also your variables should start with small letter, StudentName->studentName !
EDIT:
gpa List is collection which stores all your values which comes from InputGradeInfo().
What Sum() function is doing:
double sum = 0;
foreach(double d in gpa)
{
sum= sum + d; //(or sum+= d;)
}
In other words loop all the elements in gradeInfoList collection and make the sum of them.
About the while loop-> this loop will executes till the condition in the brackets is broken. In this case you can add many classes till you click 'y' at the end. If you click something else from 'y' you will break the loop.
I add another list creditList which you will add as parameter to the InputGradeInfo. In this list you will store every credit per class. At the end you will have gradeInfoList .Sum()/creditList.Sum() and this will give you what you want.

c# read the number of month and output the name of month

Im trying to write a C# console program to read in the number of a month and output the name of the month, and then ask the user if they want to know the number of days in that month and if so output the number of days. Assuming that there are no leap years and February ALWAYS has 28 days only.
Thanks in advance if anyone can help!!
EDIT:
This is what I have so far, I'm having trouble with the second half of the problem, I'm not sure how to ask the user if they want to know the days of the month and how to use a switch to output the number of days...
class MainClass
{
public static void Main (string[] args)
{
{
Console.WriteLine("Give me an integer between 1 and 12, and I will give you the month");
int monthInteger = int.Parse(Console.ReadLine());
DateTime newDate = new DateTime(DateTime.Now.Year, monthInteger, 1);
Console.WriteLine("The month is: " + newDate.ToString("MMMM"));
Console.WriteLine();

A simple switch case will do?
string input = Console.In.ReadLine();
int number = -1;
int.TryParse(input, out number);
switch (number)
{
case 1:
Console.Out.WriteLine("January");
break;
case 2:
Console.Out.WriteLine("February");
break;
case -1:
Console.Out.WriteLine("Please input a valid number");
break;
default:
Console.Out.WriteLine("There are only 12 months in a year");
break;
}
i take it this is enough to finish the rest of your code.
next time, please provide some code for what you have tried already, just asking for simple code usually gets you nowhere.

public static string getName(int i)
{
string[] names = { "jan", "feb", ... } // fill in the names
return names[i-1];
}

public static string getMonthName(int mounth)
{
DateTime dt = new DateTime(2000, mounth, 1);
return dt.ToString("M").Substring(0, dt.ToString("M").IndexOf(' '));
}

Based on your other related question that was closed as a duplicate of this one (https://stackoverflow.com/questions/24996241/c-sharp-number-of-days-in-a-month-using-a-switch#24996339)...
This is clearly an academic exercise that wants you to learn about the switch statement.
Here is a complete example that demonstrates a couple ways to do switch statements. Since you already grabbed the month number from the user you can switch on that value by creating a mapping between the month and the number of days in the month.
To wit:
class MainClass
{
public static void Main(string[] args)
{
Console.WriteLine("Give me an integer between 1 and 12, and I will give you the month");
int monthInteger = int.Parse(Console.ReadLine()); // WARNING: throws exception for non-integer input
Console.WriteLine(GetMonthName(monthInteger));
Console.WriteLine();
Console.Write("Display days in month (y/n)? ");
if (Console.ReadLine() == "y")
{
int daysInMonth = GetDaysInMonth_NoLeapYear(monthInteger);
if (daysInMonth > 0)
{
Console.WriteLine(String.Format("{0} days in {1}",
daysInMonth.ToString(),
GetMonthName(monthInteger)));
}
else
{
Console.WriteLine("Invalid month entered.");
}
Console.WriteLine();
}
Console.WriteLine("Hit enter to close");
Console.ReadLine();
}
private static String GetMonthName(int monthInteger)
{
DateTime newDate = new DateTime(DateTime.Now.Year, monthInteger, 1);
String monthName = newDate.ToString("MMMM");
return monthName;
}
/// <summary>
/// Prints days in month. Assumes no leap year (since no year context provided) so Feb is always 28 days.
/// </summary>
/// <param name="monthInteger"></param>
private static int GetDaysInMonth_NoLeapYear(int monthInteger)
{
int daysInMonth = -1; // -1 indicates unknown / bad value
switch (monthInteger)
{
case 1: // jan
daysInMonth = 30;
break;
case 2: // feb
daysInMonth = 28; // if leap year it would be 29, but no way of indicating leap year per problem constraints
break;
case 3: // mar
daysInMonth = 31;
break;
case 4: // apr
daysInMonth = 30;
break;
case 5: // may
daysInMonth = 31;
break;
case 6: // jun
daysInMonth = 30;
break;
case 7: // jul
daysInMonth = 31;
break;
case 8: // aug
daysInMonth = 31;
break;
case 9: // sep
daysInMonth = 30;
break;
case 10: // oct
daysInMonth = 31;
break;
case 11: // nov
daysInMonth = 30;
break;
case 12: // dec
daysInMonth = 31;
break;
}
return daysInMonth;
}
/// <summary>
/// Prints days in month. Assumes no leap year (since no year context provided) so Feb is always 28 days.
/// </summary>
/// <param name="monthInteger"></param>
private static int GetDaysInMonth_NoLeapYear_Compact(int monthInteger)
{
// uses case statement fall-through to avoid repeating yourself
int daysInMonth = -1; // -1 indicates unknown / bad value
switch (monthInteger)
{
case 2: // feb
daysInMonth = 28; // if leap year it would be 29, but no way of indicating leap year per problem constraints
break;
case 3: // mar
case 5: // may
case 7: // jul
case 8: // aug
case 10: // oct
case 12: // dec
daysInMonth = 31;
break;
case 1: // jan
case 4: // apr
case 6: // jun
case 9: // sep
case 11: // nov
daysInMonth = 30;
break;
}
return daysInMonth;
}
}
GetDaysInMonth_NoLeapYear_Compact is included only to illustrate the case fall-through behavior that lets multiple case statements go to the same code.

Month in c# using DateTime

I am wondering if there is way to have the user enter a number like 01 and have that string converted to the month using dateTime. I know how to have the user enter a string such as 01/01/2011 and have the converted to a DateTime. Is there a way to use datetime to convert a two number string into a month. Something like this, but that would work
Console.WriteLine("Please the month numerically");
string date = Console.ReadLine();
dt = Convert.ToDateTime(date).Month;

You could probably get it jumping through some hoops with DateTime, however;
CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName(int monthNumber);
is probably easier.

It is already built into the .NET framework: see System.Globalization.DateTimeFormatInfo.MonthNames

It'd be easier to just have an array of 12 elements, each being a month.
String[] Months = new String[] {"Jan", "Feb"}; //put all months in
Console.WriteLine("Please the month numerically");
string date = Console.ReadLine();
int index = 0;
if (!int.TryParse(date, out index)) {
// handle error for input not being an int
}
dt = Months[index];
If you really wanted to stick with using the DateTime class, you could take in the month and then tag on some day and year and use the method you provided in your code. For example...
dt = Convert.ToDateTime(date + "/01/2012").Month;
But this is less advised.

Your example is not complete, cause you need to specify which year and which day in the date.
Assuming that that data have to be of the current date, you can do something like this:
DateTime dt = new DateTime(DateTime.Now.Year, int.Parse("01"), DateTime.Now.Day);
Don't forget, obviously, add a couple of controls, like
Month range {1-12}
Month string is a number
EDIT
int month =-1;
if(int.TryParse(userInputString, out month)){
if(month>=1 && month <=12) {
DateTime dt = new DateTime(
DateTime.Now.Year,
month,
DateTime.Now.Day);
}
}
Hope this helps.

public static string ReturnMonthName(string pMonth)
{
switch (pMonth)
{
case "01" :
return "January";
case "02":
return "February";
case "03":
return "March";
case "04":
return "April";
case "05":
return "May";
case "06":
return "June";
case "07":
return "July";
case "08":
return "August";
case "09":
return "September";
case "10":
return "October";
case "11":
return "November";
case "12":
return "December";
default:
return "Invalid month";
}

Strip the month from your datetime and use a switch/case select to assign your variable.
switch (val)
{
case 1:
MessageBox.Show("The day is - Sunday");
break;
case 2:
MessageBox.Show("The day is - Monday");
break;
case 3:
MessageBox.Show("The day is - Tuesday");
break;
case 4:
MessageBox.Show("The day is - wednesday");
break;
case 5:
MessageBox.Show("The day is - Thursday");
break;
case 6:
MessageBox.Show("The day is - Friday");
break;
case 7:
MessageBox.Show("The day is - Saturday");
break;
default:
MessageBox.Show("Out of range !!");
break;
}

c# switch loop, adding up total for each case

I have 2 codes that I want to combine into 1 and am having a lot of trouble doing it. The code should ask for the group number then their donation amount and loop back until they press 0. Once they press 0 it should show the total for all groups. Here are the 2 different codes
code 1
using System;
public class TotalPurchase
{
public static void Main()
{
double donation;
double total = 0;
string inputString;
const double QUIT = 0;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString = Console.ReadLine();
donation = Convert.ToDouble(inputString);
while(donation != QUIT)
{
total += donation;
Console.WriteLine("Enter next donation amount, or " +
QUIT + " to quit ");
inputString = Console.ReadLine();
donation = Convert.ToDouble(inputString);
}
Console.WriteLine("Your total is {0}", total.ToString("C"));
}
}
code 2
using System;
namespace donate
{
class donate
{
public static void Main()
{
begin:
string group;
int myint;
Console.WriteLine("Please enter group number (4, 5, or 6)");
Console.WriteLine("(0 to quit): ");
group = Console.ReadLine();
myint = Int32.Parse(group);
switch (myint)
{
case 0:
Console.WriteLine("Bye.");
break;
case 4:
case 5:
case 6:
double donation;
string inputString;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString = Console.ReadLine();
donation = Convert.ToDouble(inputString);
goto begin;
default:
Console.WriteLine("Incorrect grade number.", myint);
goto begin;
}
}
}
}
So basically I want to find the total for each group using the 2nd code.
Any help would be greatly appreciated.

Don't use goto like that. Just use another while loop like you did in the first code segement.
It would be much more concise to say:
if (myInt > 3 && myInt < 7) { ... }
instead of using that switch statement.
Basically your code for summing up the donation amount does the trick, so just stick that inside a similar loop that handles what the group number is. If you do this you're going to want to use a different input to signify the end of donations vs the end of input altogether. It would be confusing if the application said "Enter 0 to quit input", followed by "Enter 0 to quit donation input".

You are very close with Code 2. If you put Code 2 inside while loop it works!
The only code I have written for you here is declared myint outside the while loop and initialised it to a non-zero value.
double total = 0;
int myint = -1;
while (myint != 0)
{
string group;
Console.WriteLine("Please enter group number (4, 5, or 6)");
Console.WriteLine("(0 to quit): ");
group = Console.ReadLine();
myint = Int32.Parse(group);
switch (myint)
{
case 0:
Console.WriteLine("Bye.");
break;
case 4:
case 5:
case 6:
double donation;
string inputString;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString = Console.ReadLine();
donation = Convert.ToDouble(inputString);
total += donation;
break;
default:
Console.WriteLine("Incorrect grade number.", myint);
break;
}
}
Console.WriteLine("Your total is {0}", total.ToString("C"));

C# How do you count the number of inputs to find the average in a switch loop?

Here is my loop that asks for the group number then the donation. I'm wondering how to count the number of donations to find the average for each group.
using System;
public class TotalPurchase
{
public static void Main()
{
double total4 = 0;
double total5 = 0;
double total6 = 0;
int myint = -1;
while (myint != 0)
{
string group;
Console.WriteLine("Please enter group number (4, 5, or 6)");
Console.WriteLine("(0 to quit): ");
group = Console.ReadLine();
myint = Int32.Parse(group);
switch (myint)
{
case 0:
break;
case 4:
double donation4;
string inputString4;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString4 = Console.ReadLine();
donation4 = Convert.ToDouble(inputString4);
total4 += donation4;
break;
case 5:
double donation5;
string inputString5;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString5 = Console.ReadLine();
donation5 = Convert.ToDouble(inputString5);
total5 += donation5;
break;
case 6:
double donation6;
string inputString6;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString6 = Console.ReadLine();
donation6 = Convert.ToDouble(inputString6);
total6 += donation6;
break;
default:
Console.WriteLine("Incorrect grade number.", myint);
break;
}
}
Console.WriteLine("Grade 4 total is {0}", total4.ToString("C"));
Console.WriteLine("Grade 5 total is {0}", total5.ToString("C"));
Console.WriteLine("Grade 6 total is {0}", total6.ToString("C"));
}
}
Any help would be appreciated.

Not sure if I fully understand your question -- but you could just add a simple counter for each group:
int donations4 = 0;
int donations5 = 0;
int donations6 = 0;
And then increment that counter in each of your switch cases, ex:
switch(myInt)
{
case 4:
...
donations4++;
break;
case 5:
...
donations5++;
break;
case 6:
...
donations6++;
break;
}
Then when you're done - simply do the math to find the average.
Although this is probably the simplest way, a better way would be to treat each group as its own object, and have the object internally track the # of donations, as well as the sum and average.
-- Dan

using System;
public class TotalPurchase
{
public static void Main()
{
double total4 = 0;
double total5 = 0;
double total6 = 0;
int numberOfInputForTotal4 = 0;
int numberOfInputForTotal5 = 0;
int numberOfInputForTotal6 = 0;
int myint = -1;
while (myint != 0)
{
string group;
Console.WriteLine("Please enter group number (4, 5, or 6)");
Console.WriteLine("(0 to quit): ");
group = Console.ReadLine();
myint = Int32.Parse(group);
switch (myint)
{
case 0:
break;
case 4:
double donation4;
string inputString4;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString4 = Console.ReadLine();
donation4 = Convert.ToDouble(inputString4);
total4 += donation4;
numberOfInputForTotal4++;
break;
case 5:
double donation5;
string inputString5;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString5 = Console.ReadLine();
donation5 = Convert.ToDouble(inputString5);
total5 += donation5;
numberOfInputForTotal5++;
break;
case 6:
double donation6;
string inputString6;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString6 = Console.ReadLine();
donation6 = Convert.ToDouble(inputString6);
total6 += donation6;
numberOfInputForTotal6++;
break;
default:
Console.WriteLine("Incorrect grade number.", myint);
break;
}
}
Console.WriteLine("Grade 4 total is {0}", total4.ToString("C"));
Console.WriteLine("Grade 5 total is {0}", total5.ToString("C"));
Console.WriteLine("Grade 6 total is {0}", total6.ToString("C"));
Console.WriteLine("Grade 4 average is {0}", (total4 / numberOfInputForTotal4).ToString("C"));
Console.WriteLine("Grade 5 average is {0}", (total5 / numberOfInputForTotal5).ToString("C"));
Console.WriteLine("Grade 6 average is {0}", (total6 / numberOfInputForTotal6).ToString("C"));
}
}
As you can see, there are 3 extra variables (one for each group) that can be used to figure out the number of inputs provided. Using that you can divide the total for each group by the number of input in each group separately.

Just declare count for each group as well as total and increment in the case statement:
case 4:
double donation4;
string inputString4;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString4 = Console.ReadLine();
donation4 = Convert.ToDouble(inputString4);
total4 += donation4;
count4++; // HERE!!!!
break;
Alternatively, you can use List<int> which will calculate your average as well:
List<int> list4 = new List<int>();
and
case 4:
double donation4;
string inputString4;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString4 = Console.ReadLine();
donation4 = Convert.ToDouble(inputString4);
list4.Add(donation4);
break;
and
Console.WriteLine(list4.Average());

Just keep track of the count yourself with another variable. count4, count5, etc.

For bonus points in your homework assignment:
1) Sanitize your group number input - ie check to see if the user typed in a valid number.
2) Don't call the variable myInt. Call it groupNum, or something that describes the function, not the implementation of the variable.
3) Use an array for donation totals and counts
ie,
int[] donationCount= new int[MAX_GROUP+1]; // figure out yourself why the +1
int[] donationTotal= new int[MAX_GROUP+1];
// initialize donationCount and donationTotal here
then in your loop (don't even need switch):
++donationCount[groupNum];
donationTotal[groupNum] += donationAmount; // did you notice that you moved the reading of donationAmount out of the switch?

I would go with changing your doubles to List and using the Sum() and Average() methods on your Lists at the end. Your code would look like this after this change.
using System;
using System.Collections.Generic;
using System.Linq;
public class TotalPurchase
{
public static void Main()
{
List<double> total4 = new List<double>();
List<double> total5 = new List<double>();
List<double> total6 = new List<double>();
int myint = -1;
while (myint != 0)
{
string group;
Console.WriteLine("Please enter group number (4, 5, or 6)");
Console.WriteLine("(0 to quit): ");
group = Console.ReadLine();
myint = Int32.Parse(group);
switch (myint)
{
case 0:
break;
case 4:
double donation4;
string inputString4;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString4 = Console.ReadLine();
donation4 = Convert.ToDouble(inputString4);
total4.Add(donation4);
break;
case 5:
double donation5;
string inputString5;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString5 = Console.ReadLine();
donation5 = Convert.ToDouble(inputString5);
total5.Add(donation5);
break;
case 6:
double donation6;
string inputString6;
Console.WriteLine("Please enter the amount of the contribution: ");
inputString6 = Console.ReadLine();
donation6 = Convert.ToDouble(inputString6);
total6.Add(donation6);
break;
default:
Console.WriteLine("Incorrect grade number.", myint);
break;
}
}
if(total4.Count > 0)
Console.WriteLine("Grade 4 total is {0}; Average {1}", total4.Sum().ToString("C"), total4.Average().ToString("C"));
if(total5.Count >0)
Console.WriteLine("Grade 5 total is {0}; Average {1}", total5.Sum().ToString("C"), total5.Average().ToString("C"));
if (total6.Count > 0)
Console.WriteLine("Grade 6 total is {0}; Average {1}", total6.Sum().ToString("C"), total6.Average().ToString("C"));
}
}