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How can I convert String to Int?
(31 answers)
Closed 7 years ago.
private void textBox1_TextChanged(object sender, EventArgs e)
{
var x = textBox1.Text;
var y = 1000000;
var answer = x * y;
}
This is my current code. I want to take the user input from textBox1 and multiply it by 1000000 because it needs to convert the user input. But This code doesn't because x technically isn't a numerical value. How would I get this functioning?
This is getting text, not a number:
var x = textBox1.Text;
Since C# is statically typed, you need to explicitly turn it into a number. For this you can use something like int.TryParse(). For example:
var xText = textBox1.Text;
var x = 0;
if (!int.TryParse(xText, out x))
{
// display an error to the user
return;
}
var y = 1000000;
var answer = x * y;
That way you're testing if the text input can be parsed as a number and, if it can't, displaying a message to the user. Rather than assuming the input and getting an unhandled exception.
There are also TryParse() methods for other numeric types, in case you want to use something like a double or a float for other calculations.
You can use Int32.Parse if you're sure user input is a number or int.TryParse if you need to validate it.
I'm assuming integer inputs only what could be wrong though. Same applies for other numeric types. (they all have Parse and TryParse)
Using Int32.Parse
private void textBox1_TextChanged(object sender, EventArgs e)
{
var x = Int32.Parse(textBox1.Text); // you're sure text is numeric
var y = 1000000;
var answer = x * y;
}
Using Int32.TryParse
private void textBox1_TextChanged(object sender, EventArgs e)
{
int x = 0;
if (Int32.TryParse(textBox1.Text, out x)) // you're NOT sure if text is numeric
{
var y = 1000000;
var answer = x * y;
}
else
{
// let the user know that numeric values are required
}
}
This will get you your numerical values
private void textBox1_TextChanged(object sender, EventArgs e)
{
float x = Float.Parse(textBox1.text, CultureInfo.InvariantCulture);
float y = 1000000;
float answer = x * y;
}
Related
I have a textbox on my design form that have multiple numbers of double data type. I have a class that has a method to calculate smallest difference (positive or negative) between two consecutive numbers.
public decimal FindSmallestPriceChange()
{
}
On my form there is a label to display the result and a button event that calls the above method to calculate and display the smallest change between consecutive numbers in the text box.
private void btnSmallest_Click(object sender, EventArgs e)
{
lblSmallest.Text = aAnalyzer.FindSmallestPriceChange().ToString();
}
I have an array mentioned in the form class :
decimal[] prices = Array.ConvertAll(stringPrices, decimal.Parse);
I know I have to use for loop in my FindSmallest method but I don't know how to use the elements from the text box on design form in my separate class.
Can someone guide me on the right path on this.
The structure could be something like the following.
private void btnSmallest_Click(object sender, EventArgs e)
{
var stringPrices = new List<string>();
stringPrices.Add(comboBox1.Text);
stringPrices.Add(comboBox2.Text);
//TODO add error handling
decimal[] prices = Array.ConvertAll(stringPrices, decimal.Parse);
lblSmallest.Text = aAnalyzer.FindSmallestPriceChange(prices).ToString();
}
(...)
public static decimal FindSmallestPriceChange(IEnumerable<decimal> prices)
{
// There are many ways to do this. Here is one.
var sorted = prices.ToList();
sorted.Sort();
if( prices.Count() < 2 ) return 0;
decimal min = sorted[1] - sorted[0];
for(int i = 2; i < sorted.Count() - 1 ; i++ ) {
var diff = sorted[i-1] - sorted[i];
if( diff < min ) min = diff;
}
return min;
}
Test
Console.WriteLine(FindSmallestPriceChange(new []{66.6m}));
Console.WriteLine(FindSmallestPriceChange(new []{1m, 2m}));
Console.WriteLine(FindSmallestPriceChange(new []{1.1m, 4.4m, 2.2m}));
Console.WriteLine(FindSmallestPriceChange(new []{4.4m, -1.1m, 0m, 1.1m, 2.2m, }));
Output
0
1
1.1
-1.1
Getting this error at futureValue = this.CalculateFutureValue(futureValue, monthlyInvestment, monthlyInterestRate, months);and I'm having trouble figuring out how to fix it. When I look up the error online most of the answers say to make the method decimal instead of void so it can have a return type.
But in part of the requirements for the code "rework the CalculateFutureValue method by making it a void function and adding a fourth parameter representing the future value amount to be returned by this method."
private void btnCalculate_Click(object sender, EventArgs e)
{
decimal monthlyInvestment = Convert.ToDecimal(txtMonthlyInvestment.Text);
decimal yearlyInterestRate = Convert.ToDecimal(txtInterestRate.Text);
int years = Convert.ToInt32(txtYears.Text);
int months = years * 12;
decimal monthlyInterestRate = yearlyInterestRate / 12 / 100;
decimal futureValue = 0m;
futureValue = this.CalculateFutureValue(futureValue, monthlyInvestment, monthlyInterestRate, months);
txtFutureValue.Text = futureValue.ToString("c");
txtMonthlyInvestment.Focus();
}
/
private void CalculateFutureValue(decimal futureValue, decimal monthlyInvestment, decimal monthlyInterestRate, int months)
{
for (int i = 0; i < months; i++)
{
futureValue = (futureValue + monthlyInvestment) * (1 + monthlyInterestRate);
}
}
Here is what they mean by the requirement: instead of this
decimal ComputeSomething(decimal x, decimal y) {
return x*x + y*y;
}
...
decimal result = ComputeSomething(10.234M, 20.5M);
do this:
void ComputeSomething(decimal x, decimal y, out res) {
res = x*x + y*y;
}
...
decimal result;
ComputeSomething(10.234M, 20.5M, out result);
Note the out qualifier in front of the additional parameter res. This means that the parameter is "output", i.e. your method must assign it some value before completion.
The assignment to res inside ComputeSomething will become an assignment to variable result.
You need to pass the variable by reference:
private void CalculateFutureValue(ref decimal futureValue, decimal monthlyInvestment, decimal monthlyInterestRate, int months){ ... }
and
this.CalculateFutureValue(ref futureValue, monthlyInvestment, monthlyInterestRate, months);
See this documentation.
If futureValue had not been initialized with a value before passing it to CalculateFutureValue, the out keyword would have needed to be used in place of ref.
private void textBox1_TextChanged(object sender, EventArgs e)
{
int x = 0;
if (Int32.TryParse(textBox1.Text, out x))
{
var y = 1000000;
var answer = x * y;
displayLabel2.Text = answer.ToString();
}
else
{
displayLabel2.Text = "error";
}
}
All of this code works. But I don't know how to use it if a decimal is inputed. Currently it reads numerical values fine and calculates them fine. But I need it to allow decimal points to be inputted.
Ex. if someone inputed 4.7, then I need 4.7 to be multiplied by 1000000.
You need to use a number type that has precision. You can use either floating types (double or float) or the decimal type.
private void textBox1_TextChanged(object sender, EventArgs e)
{
decimal x = 0;
if (decimal.TryParse(textBox1.Text, out x))
{
var y = 1000000.0M;
var answer = x * y;
displayLabel2.Text = answer.ToString();
}
else
{
displayLabel2.Text = "error";
}
}
You could use decimal instead of int:
decimal x = 0;
if (decimal.TryParse(textBox1.Text, out x))
I am working on a employee paycheck calculator using several private methods. The methods will determine overtime hours and regular hours. I also must create methods for regular pay and overtime pay. My question is can I feed the results from the hours methods into the methods that will determine pay? If that is possible, how would it work? The method in question is CalculateBasePayAmount--can I pass a result from another method into here?
Here is a look at what I've got so far. Thanks for any help anyone could provide!
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
//Determine Hours Method
private decimal DetermineBasePayHours(decimal parhoursWorked)
{
decimal baseHours = 0;
decimal overtimeHours = 0;
if (parhoursWorked <= 40)
{
baseHours = parhoursWorked;
}
else if (parhoursWorked > 40)
{
overtimeHours = parhoursWorked - 40;
baseHours = parhoursWorked - overtimeHours ;
}
return baseHours;
}
private decimal DetermineOverTimeHours(decimal parHoursWorked, string parCategory)
{
decimal overtimeHours = 0;
if (parHoursWorked > 40 && parCategory!="MGR")
{
overtimeHours = parHoursWorked - 40;
}
return overtimeHours;
}
private decimal CalculateBasePayAmount(decimal basePayHours, string parCategory)
{
decimal basePay = 0;
decimal mgrWage = 20;
decimal salesWage = 15;
decimal staffWage = 10;
basePayHours= DetermineBasePayHours(basePayHours);
if(parCategory == "MGR" && basePayHours > 40)
{
basePay = 40 * mgrWage;
}
else
{
basePay = basePayHours * mgrWage;
}
if (parCategory =="SR")
{
basePay = basePayHours * salesWage;
}
else if (parCategory == "STF")
{
basePay = basePayHours * staffWage;
}
return basePay;
}
protected void butCalcPay_Click(object sender, EventArgs e)
{
////1. Declare Variables
//decimal mgrWage = 20;
//decimal salesWage = 15;
//decimal staffWage = 10;
//decimal basePay = 0M;
//decimal salesOvertime = 22.50M;
//decimal staffOvertime = 15;
//decimal overtimeHours = 0;
//decimal overtimePay = 0;
//decimal totalPay = 0;
decimal totalHours = 0;
decimal bpHours;
decimal otHours;
string empCat;
decimal basePay;
//2. Get Values for Variables
totalHours = Convert.ToDecimal(txtNumberHours.Text);
empCat = Convert.ToString(ddlCategory.SelectedValue);
// 3. Methods Called
bpHours = DetermineBasePayHours(totalHours);
otHours = DetermineOverTimeHours(totalHours, empCat);
basePay = CalculateBasePayAmount(totalHours, empCat);
// 4. Display Results
lblbasePay.Text = "Base Pay " + basePay.ToString("C");e here
can I feed the results from the hours methods into the methods that will determine pay?
In a manner of speaking, yes. Though I think the confusion is coming from the way you describe it and the terminology you use.
It's not entirely clear to me what specific values you're looking for in this case, but it looks like your methods essentially just accept some values, run some calculations, and return some values. Any code which call those functions will then get those returned values and can use them to call other functions. As a contrived example:
private int Method1(int someValue)
{
// perform some calculation, then...
return anotherValue;
}
private int Method2(int someValue)
{
// perform some calculation, then...
return anotherValue;
}
Then consuming code would be able to use those functions to perform larger calculations:
var calculatedValue = Method1(5);
var furtherCalculatedValue = Method2(calculatedValue);
This essentially "feeds the results" of the first function into the second function, in the sense that the result of the first function is then used as an input for the second function. The functions don't have any knowledge of each other, they don't "feed data to each other", in this case they simply return values based on calculations. Consuming code can choose to use the result of one function as a parameter to another function.
You do need to read more on programming and how/why we have methods that return values that the ones you mentioned above. Using your code above you'll want to use their values like this:
// basePayHours is the decimal amount returned by DetermineBasePayHours.
var basePayHours = DetermineBasePayHours(parhoursWorked);
// overTimeHours is the decimal amount returned by DetermineOverTimeHours.
var overTimeHours = DetermineOverTimeHours(parHoursWorked, parCategory);
// basePayAmount is the decimal amount returned by CalculateBasePayAmount.
var basePayAmount = CalculateBasePayAmount(basePayHours, parCategory);
delegate can also be used when a method is needed from another one .
Background:This is updated from 13 hours ago as I have been researching and experimenting with this for a few. I'm new to this programming arena so I'll be short, I'm teaching myself C# And I'm trying to learn how to have integers from a user's input into a textbox get calculated from a button1_Click to appear on the form. Yes, this is a class assignment but I think I have a good handle on some of this but not all of it; that's why I'm turning to you guys.
Problem:
I'm using Microsoft Visual Studio 2010 in C# language, Windows Forms Application and I need to create a GUI that allows a user to enter in 10 integer values that will be stored in an array called from a button_Click object. These values will display the highest and lowest values that the user inputted. The only thing is that the array must be declared above the Click() method.
This is what I have come up with so far:
namespace SmallAndLargeGUI
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
public void inputText_TextChanged(object sender, EventArgs e)
{
this.Text = inputText.Text;
}
public void submitButton_Click(object sender, EventArgs e)
{
int userValue;
if(int.TryParse(inputText.Text, out userValue))
{
}
else
{
MessageBox.Show("Please enter a valid integer into the text box.");
}
int x;
x = Convert.x.ToString();
int squaredResults = squared(x);
int cubedResults = cubed(x); squared(x);
squaredLabel.Text = x.ToString() + " squared is " + squaredResults.ToString();
cubedLabel.Text = x.ToString() + " cubed is " + cubedResults.ToString();
}
public static int squared(int x)
{
x = x * x;
return x;
}
public static int cubed(int x)
{
x = x * squared(x);
return x;
}
}
}
Now I can't run this program because line 38 shows an error message of: 'System.Convert' does not contain a definition for 'x' Also I still have to have an array that holds 10 integers from a textbox and is declared above the Click() method. Please guys, any help for me? This was due yesterday.
This looks like homework, so you should try a bit more than that. Here is what you could do: parse the string (say it's a comma-separated list of numbers), cast each value to int and populate your array. You can either call .Max() / .Min() methods or loop through the values of the array and get the max / min value. Here is a bit of code:
int n = 10;
int[] numbers = (from sn in System.Text.RegularExpressions.Regex.Split(inputText.Text, #"\s*,\s*") select int.Parse(sn)).ToArray();
int max = numbers.Max();
int min = numbers.Min();
//int max = numbers[0];
//int min = numbers[0];
//for(int i = 1; i < n; i++)
//{
// if(max < numbers[i])
// {
// max = numbers[i];
// }
// if(min > numbers[i])
// {
// min = numbers[i];
// }
//}
This in all probability being a homework I will not provide entire solution but just provide a hint.
Task to me seems to be to some how accept 10 integers and then show smallest and largest of them. For this there is no need to maintain an array (off-course only if maintaining an array is itself not part of the problem). You just need to keep track of current minimum and current maximum.
As and when you receive an input compare it with the current minimum and maximum and update them accordingly. e.g.
if(num < curr_min) curr_min = num;