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Why do I need a double? [duplicate]

This question already has answers here:
C# short/long/int literal format?
(5 answers)
Closed 2 years ago.
Simply put, I'm very new and I do not understand why I need total to be a double, my teacher put it as a float in his program, but it doesn't work for me.
int choix;
double total = 0;
do
{
Console.WriteLine("Menu\n\n");
Console.WriteLine("1 - Pizza 3.25$\n");
Console.WriteLine("2 - Poutine 2.75$\n");
Console.WriteLine("3 - Liqueur 1.25$\n");
Console.WriteLine("4 - Fin\n\n");
Console.WriteLine("Votre choix(1 - 4)");
choix = int.Parse(Console.ReadLine());
switch(choix)
{
case 1:total = total + 3.25;
break;
case 2:total = total + 2.75;
break;
case 3:total = total + 1.25;
break;
case 4:Console.WriteLine("Voici le total " + total);
break;
default:Console.WriteLine("Erreur de choix");
break;
}
}
while (choix != 4);
Sorry for this dumb question, but I cannot find answers anywhere.

Basically because of how c# interprets the code, c# doesnt know whether your decimal numbers will overflow or not, so it automatically assign all floating values as a double (which can actually hold more values than a float). So what you need to do in order to the compiler understand that you actually want a float, is to add an f at the end of the numbers.
int choix;
float total = 0;
do
{
Console.WriteLine("Menu\n\n");
Console.WriteLine("1 - Pizza 3.25$\n");
Console.WriteLine("2 - Poutine 2.75$\n");
Console.WriteLine("3 - Liqueur 1.25$\n");
Console.WriteLine("4 - Fin\n\n");
Console.WriteLine("Votre choix(1 - 4)");
choix = int.Parse(Console.ReadLine());
switch (choix)
{
case 1:
total = total + 3.25f;
break;
case 2:
total = total + 2.75f;
break;
case 3:
total = total + 1.25f;
break;
case 4:
Console.WriteLine("Voici le total " + total);
break;
default:
Console.WriteLine("Erreur de choix");
break;
}
}
while (choix != 4);

What instructions can be used to perform a series of calculations in a calculator?

I wrote a calculator program in the Blazor framework, but my code only runs the Calculate method once, and if I want to do another operation I have to run the program again, how can I solve this problem?
public async Task Calculate()
{
if (Result != " ")
{
_firstnumber = double.Parse(Result);
Result = " ";
switch (_operand)
{
case "+":
Result = (_secondnumber + _firstnumber).ToString();
break;
case "-":
Result = (_secondnumber - _firstnumber).ToString();
break;
case "*":
Result = (_secondnumber * _firstnumber).ToString();
break;
case "/":
Result = (_secondnumber / _firstnumber).ToString();
break;
}
}
await LocalStorageService.SetItemAsync("Result", Result);
}
You can see the full code in this link:
https://github.com/elnaz25/GitRepos

https://lupblazorcalculator.z20.web.core.windows.net/
https://github.com/Lupusa87/BlazorCalculator
Please check my blazor calculator, I hope you will find answer.

console.clear placement within a looping program

Hi i have been looking for where to put my console.clear because i have made a looping program but i would like to clear after use. Could any one tell me where to put a console.clear or give me a push in the right direction at least. Sorry i am very new to C# and have an assignment due in pretty soon and i am panicing that i havent got my Console.Clear command sorted yet. Here is my code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Assignment_test
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
//when creating the variable i would of used byte however it wasn't picking it up so i had to use int which i know isnt effective use of memory
int sUserChoice = 0;
do
{
//this makes the text yellow
Console.ForegroundColor = ConsoleColor.Yellow;
Console.WriteLine("Welcome to Hit ‘n’ Miss Ltd");
Console.WriteLine("Please select an option:");
Console.WriteLine("\n\n 1 for Welcoming to the system");
Console.WriteLine("\n 2 for the mean of grades of the class");
Console.WriteLine("\n 3 for what month it is");
Console.WriteLine("\n 4 for adds numbers between -10 and +10 and adds them together");
Console.WriteLine("0 is quit");
Console.Write("\n Please enter a number: ");
int.TryParse(Console.ReadLine(), out sUserChoice);
　
　
　
　
　
　
switch (sUserChoice)
{
case 1:
//here i say that to start talking about the parameter that i shall be using
WelcomeToTheSystem();
break;
case 2:
// here i call apon the parameter used
Grades();
break;
case 3:
// here i call apon the parameter used
Months();
break;
case 4:
// here i call apon the parameter used
AddingNegitiveAndPossitiveNumbers();
break;
// here i call apon the parameter used
case 0:
Quit();
break;
}
} while (sUserChoice != 0);
　
　
Console.ReadKey();
}
//start of prodecdures and funtions
private static int DataVaildation()
{
//variables
bool bUserInput;
int iNumber;
//below is a loop that runs at least once. the loop continues
//iterating while the condition evaluates to true, otherwise it ends
//and control goes to the statement immediately after it.
do
{
Console.Write("Please enter a number: ");
//converts string into int
bUserInput = Int32.TryParse(Console.ReadLine(), out iNumber);
//this will be true if the user input could not be converted for instance a word is used
if (!bUserInput)
{
Console.WriteLine("Input could not be converted into an integer number");
continue;
}
//the validation so if the inputted number from the user it will reject int and do the console.writeline.
if (iNumber < -11 || iNumber < 11)
{
//the error message
Console.WriteLine("Your are out of range please stay between -10 and +10");
bUserInput = false;
}
//the number is in range
else
{
Console.WriteLine("Vaild number!");
//if bUserInput is true then the loop can end.
bUserInput = true;
}
} while (!bUserInput);//while this evaluates to true, the loop continues.
return iNumber;
}
//option 4
private static void AddingNegitiveAndPossitiveNumbers()
{
Console.WriteLine("Please give me 2 number between -10 and +10 and ill add them together\n");
//calls apon the private static int above
int iNumber1 = DataVaildation();
int iNumber2 = DataVaildation();
//the adding will be done here
int iResult = iNumber1 + iNumber2;
Console.WriteLine("The sum of {0} + {1} is {2}", iNumber1, iNumber2, iResult);
}
//data validation
//option 3
private static void Months()
{
Console.WriteLine("so pick a number between 1 and 12. 1 is january and 12 december");
//here i declare that int is a variable
int iMonths = 0;
//i then will tryparse if someone inputs an invalid number
int.TryParse(Console.ReadLine(), out iMonths);
Console.ReadKey();
//i start a switch statement
switch (iMonths)
{
//if the user selects a number it will display the month this is done by using case to get the users input
case 1:
Console.WriteLine("It's January");
break;
case 2:
Console.WriteLine("It's Febuary");
break;
case 3:
Console.WriteLine("It's March");
break;
case 4:
Console.WriteLine("It's April");
break;
case 5:
Console.WriteLine("It's May");
break;
case 6:
Console.WriteLine("It's June");
break;
case 7:
Console.WriteLine("It's July");
break;
case 8:
Console.WriteLine("It's August");
break;
case 9:
Console.WriteLine("It's September");
break;
case 10:
Console.WriteLine("It's October");
break;
case 11:
Console.WriteLine("It's Novemeber");
break;
case 12:
Console.WriteLine("It's December");
break;
}
}
//0
private static void Quit()
{
//this bit exits the code if you press 0
System.Environment.Exit(0);
}
//1
private static void WelcomeToTheSystem()
{
Console.WriteLine("Please enter a name: ");
//used string here because its text
string sName =
Console.ReadLine();
Console.WriteLine("Welcome to the system: " + sName);
Console.ReadKey();
}
//2
private static void Grades()
{
int[] array1 = new int[15];
Console.WriteLine("please give me 15 numbers and i will give you the average of them");
for (int i = 0; i < array1.Length; i++)
{
while (int.TryParse(Console.ReadLine(), out array1[i]) == false)
{
Console.WriteLine("Please give me a number not text");
}
}
////here the averaging takes place it basscially averages the array that it has and adds + to every user input
Console.WriteLine("The average is {0} / 15 = {1}", string.Join("+", array1), array1.Average());
}
}
}

I would suggest place it at the beging of your cycle.
something like this:
do
{
...
//this makes the text yellow
Console.Clear();
Console.ForegroundColor = ConsoleColor.Yellow;
...
}

I would suggest writing a small method that asks if you want to continue. If so, Clear screen and then re-display everything
private static void WouldYouLikeToContinue()
{
Console.Write("Would you like to continue? [n to quit]: ");
string input = Console.ReadLine();
if (input.ToLower() == "n")
Quit();
Console.Clear(); // <--- This is where I would suggest adding the Clear.
}
you can use this method after the switch block
switch (sUserChoice)
{
case 1:
//here i say that to start talking about the parameter that i shall be using
userName = WelcomeToTheSystem();
break;
case 2:
// here i call apon the parameter used
Grades();
break;
case 3:
// here i call apon the parameter used
Months();
break;
case 4:
// here i call apon the parameter used
AddingNegitiveAndPossitiveNumbers();
break;
// here i call apon the parameter used
case 0:
Quit();
break;
}
WouldYouLikeToContinue(); // <----- HERE
} while (sUserChoice != 0);
NOTE: Your method to validate data... has a syntax error.
if (iNumber < -11 || iNumber > 11) // iNumber should be > 11 (not < 11)

Need help Improving Basic C# Calculator [closed]

Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 3 years ago.
Improve this question
I made this Basic C# Calculator to reflect on what I've learned these past few days. I'm an absolute beginner and I wanted to get suggestions on improving and shortening it.
I've tried to add switch statements and multiple methods, but it has been really hard grasping them.
using System;
namespace lol
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Hi! What is your name?");
string name = Console.ReadLine();
Console.WriteLine(name + " What do you wanna do?");
Console.WriteLine("Type \"+\" for addition");
Console.WriteLine("Type \"-\" for Subraction");
Console.WriteLine("Type \"*\" for Multiplication");
Console.WriteLine("Type \"/\" for division");
string operation = Console.ReadLine();
Console.Write("Now, Give me number one: ");
double num1 = Convert.ToDouble(Console.ReadLine());
Console.Write("Now give me number two: ");
double num2 = Convert.ToDouble(Console.ReadLine());
if (operation == "+")
{
Console.WriteLine(num1 + num2);
}
else if (operation == "-")
{
Console.WriteLine(num1 - num2);
}
else if (operation == "*")
{
Console.WriteLine(num1 * num2);
}
else
{
Console.WriteLine(num1 / num2);
}
}
}
}

If it better for your eyes, you can write like that:
static class Program
{
static void Main(string[] args)
{
Console.WriteLine("Hi! What is your name?");
string name = Console.ReadLine();
Console.WriteLine(name + " What do you wanna do?");
string[] operations = new string[] { "\"+\" for addition", "\"-\" for subtraction", "\"*\" for multiplication", "\"/\" for divsion" };
foreach (string operation in operations) { Console.WriteLine("Type " + operation); }
string cmd = Console.ReadLine();
Console.Write("Now, Give me number one: ");
double num1 = Convert.ToDouble(Console.ReadLine());
Console.Write("Now give me number two: ");
double num2 = Convert.ToDouble(Console.ReadLine());
switch (cmd)
{
case "+": Console.WriteLine(num1 + num2); break;
case "-": Console.WriteLine(num1 - num2); break;
case "*": Console.WriteLine(num1 * num2); break;
case "/": Console.WriteLine(num1 / num2); break;
}
}
}

Using enums and checking if the user input is valid. I also added a loop that checks if the user wants to input equations.
References:
double.TryParse
Enum
Switch Case
You can try it here: https://dotnetfiddle.net/aIwX5P
using System;
public class Program
{
enum eOperator
{
opAdd = 0,
opSub = 1,
opDiv = 2,
opMul = 3,
opInvalid = int.MinValue + 1,
opQuit = int.MinValue
}
public static void Main()
{
double a = 0.0, b = 0.0;
eOperator op = eOperator.opQuit;
string input = String.Empty;
Console.WriteLine("Calculator");
Console.WriteLine("Enter 'quit' at any time to exit.");
// repeat until the user wants to quit.
do // while(op != eOperator.opQuit)
{
Console.Write("a = ");
input = Console.ReadLine().ToLower().Trim();
if (double.TryParse(input, out a))
{
// input is a valid double and was stored in a
Console.Write("Operator: ");
input = Console.ReadLine().ToLower().Trim();
switch (input)
{
case "+":
op = eOperator.opAdd;
break;
case "-":
op = eOperator.opSub;
break;
case "*":
op = eOperator.opMul;
break;
case "/":
op = eOperator.opDiv;
break;
case "quit":
op = eOperator.opQuit;
break;
default:
op = eOperator.opInvalid; // can't be left as quit
Console.WriteLine("Invalid entry. +, -, *, / or quit for operator.");
break;
}
if (op != eOperator.opQuit && op != eOperator.opInvalid)
{
// user didn't choose to quit or type something invalid
Console.Write("b = ");
input = Console.ReadLine().ToLower().Trim();
if (double.TryParse(input, out b))
{
// input is a valid double and was parsed into b
double result = a; // we use the operator on a, so we might as well just store a into the result right away.
// do the operation on result.
switch (op)
{
case eOperator.opAdd:
result += b;
break;
case eOperator.opSub:
result -= b;
break;
case eOperator.opMul:
result *= b;
break;
case eOperator.opDiv:
// Div by 0 check. without this, this still works since double has +/- inf values.
if (b != 0.0) // comparing double with = and != is usually bad idea, but 0.0 is saved without rounding errors.
{
result /= b;
}
else
{
Console.WriteLine("Div by 0");
op = eOperator.opInvalid;
}
break;
default:
// this if branch checked for the other two operators. since we never chanced op after that check, this exception should never happen.
// it is still a good idea to include it to find errors in your logic, should they have occurred.
throw new Exception("This shouldn't happen.");
}
if (op != eOperator.opInvalid)
{
Console.WriteLine("Result: " + result.ToString());
}
// the only invalid operation is div by 0 for now. the message was sent to the user in that case, so no else is needed at this point.
// alternatively you can store an error message into a string, and when op = opInvalid, then display that error message here centralized.
// this would be a good idea if multiple things can go wrong.
}
else if (input == "quit")
{
// input for b was an invalid number, but input was 'quit'
op = eOperator.opQuit;
}
else
{
// input for b was an invalid number and also not 'quit', display error message
Console.WriteLine("Invalid entry. Type a number or Quit");
}
}
}
else if (input == "quit")
{
// input for a was invalid number, but 'quit'
op = eOperator.opQuit;
}
else
{
// input for a was invalid number and also not 'quit'
Console.WriteLine("Invalid entry. Type a number or Quit");
}
// repeat until the user wants to quit.
}while(op != eOperator.opQuit);
Console.WriteLine("Bye");
}
}

C# switch case how to calculate

Hey I´am trying to add two numbers together via switch case.
I have 3 inputs, number 1 and number 2. The 3rd input is the method which I´d like to calculate number 1 and 2 with(e.g +, -, *, /, etc...)
Now the problem is how do I create something like "this" ? I´ve tried this way, but it does not work...
Is it possible to make switch case like this : case %: ???
Thanks
string firstNumber;
string secondNumber;
string method;
//get numbers
Console.WriteLine ("Get first number");
firstNumber = Console.ReadLine ();
Console.WriteLine ("get 2nd number");
secondNumber = Console.ReadLine ();
Console.WriteLine ("the method to calculate with");
Console.WriteLine (" 1:\"*\"");
Console.WriteLine (" 2:\"/\"");
Console.WriteLine (" 3:\"+\"");
Console.WriteLine (" 4:\"-\"");
method = Console.ReadLine ();
//convert
int methodNew = Convert.ToInt32 (method);
int firstNumberNew = Convert.ToInt32 (firstNumber);
int secondNumberNew = Convert.ToInt32 (secondNumber);
switch (methodNew) {
case 1:
firstNumberNew *= secondNumberNew;
break;
default:
Console.WriteLine ("check the methods.");
break;
}
Console.WriteLine (methodNew);

Of course, you can read in a char and do a switch-case
for it:
int c = Console.Read(); // read from console
switch(c) {
case '/':
// work
break;
case '%':
// work
break;
case '*':
// work
break;
case '+':
// work
break;
}

First get the operator then use switch like this:
char method = Console.ReadKey().KeyChar;
double result = 0.0;
switch (method)
{
case '+':
result = firstNumberNew + secondNumberNew;
break;
case '-':
result = firstNumberNew - secondNumberNew;
break;
case '/':
result = firstNumberNew / secondNumberNew;
break;
case '%':
result = firstNumberNew % secondNumberNew;
break;
default:
Console.WriteLine("Invalid value, try again");
break;
}
Console.WriteLine(result);
It would be better if you change the type of firstNumberNew and secondNumberNew to double.Alşo you can use a while loop to force user to enter a valid character.