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I need to make some(logical multiplication) program but I cannot fix one of error [duplicate]

This question already has answers here:
Operator '&' cannot be applied to operands of type 'string' and 'string'
(2 answers)
Closed 2 years ago.
using System;
using System.Threading.Tasks;
namespace ConsoleApp11
{
class Program
{
static async Task Main(string[] args)
{
Console.WriteLine("Let's do some logical multiplication, shall we?(In binary notation (press 'Enter' to continue))");
if (Console.ReadKey().Key != ConsoleKey.Enter)
Environment.Exit(38250968);
Console.WriteLine("Let's enter some arguments for it?(press 'Enter' to continue)");
if (Console.ReadKey().Key != ConsoleKey.Enter)
Environment.Exit(38250968);
Console.WriteLine("Enter the value of argument Q and then press 'Enter'");
int q = Convert.ToInt32 (Console.ReadLine());
string w = Convert.ToString(q, 10);
Console.WriteLine("Enter the value of argument E and then press 'Enter'");
int e = Convert.ToInt32(Console.ReadLine());
string r = Convert.ToString(e, 10); ;
string t = Convert.ToString($"{w&r}"); //error is on this line
Console.WriteLine("Making some magic. Please wait");
await Task.Delay(1024);
#pragma warning disable CA2241 // Provide correct arguments to formatting methods
Console.WriteLine("The magic worked, and we got a response of");
double i = Convert.ToDouble(t);
Console.WriteLine($"{i}");
#pragma warning restore CA2241 // Provide correct arguments to formatting methods
await Task.Delay(1024);
Console.WriteLine("Press any key to exit");
Console.ReadKey();
Environment.Exit(3948);
}
}
}
How can I fix it? Shows "CS0019: Operator '&' cannot be applied to the operand of type 'string' and 'string'". I don't found a really valuable solution, so I ask you for help

you can use + operator instead of &.

While the & operator in VB.net will concatenate strings, in C# it has a total other meaning, namely a boolean or bitwise logical AND. But that's definitely not what you need here.
To correct your error, change the line on which the error occurs with this:
string t = Convert.ToString($"{w + r}"); //error is no longer on this line
or, even simpeler, since no conversion is needed, as w and r are already strings, and the concatenation result as well:
string t = w + r;

If your intend was to do a logical AND operation, you should do this with the integer numbers q and e that you already converted.
If you need the result as string you could convert it after the logical operation
string t = Convert.ToString(q & e);

You cannot do that for string, however you can try this
int t = q & e;
decimal output = Convert.ToDecimal(t);

I don't understand string in c# [duplicate]

This question already has answers here:
Cannot implicitly convert type 'int' to 'string'
(4 answers)
Closed 2 years ago.
As someone who's only ever used c++, i'm so confused. I've gone over different explanations but i still can't seem to understand it. Why do i, for example, need to check if a string is a string? (the tryparse method) If it's a number obviously its an int...right?? So for example my current code takes in age in one function and outputs it in the main function. I tried converting it to int but i got error cs0019: Operator '==' cannot be applied to operands of 'int' and 'string'
public static string GetAge()
{
Console.WriteLine("\nPlease input age > ");
int age = Int32.Parse(Console.ReadLine());
if (age == "")
{
do {
Console.Write("Invalid input. Please try again > ");
age = Console.ReadLine();
} while ( age == "");
}
return age;
}
static void Main (){
Console.WriteLine("\nPlease note\nThis program is only applicable for users born between 1999 and 2010");
string name = GetName();
string year = GetYear();
int age = GetAge();
And then i also get this error cs0029:Cannot implicitly convert type 'int' to 'string' (line 49 which is return age) and error cs0029: cannot implicitly convert type 'string' to 'int' for line 58 (int age =GetAge();)

int.Parse will throw an exception if it fails. I would modify your loop to this:
int age;
while (!int.TryParse(Console.ReadLine(), out age))
Console.Write("Invalid input. Please try again > ");
return age;
int.TryParse will return true upon success.
Also change the method definition to return an int instead:
public static int GetAge()

I don't understand what do you want and why. :-)
You don't need to check string is string.
int.Parse will throwing an exception, when the input is not a valid integer, but you can use TryParse, what is returns a boolean and does not throw exception.
In C# you can't compare integers and strings, you must convert it first.
Your GetAge method returns integer, but the return type declared as string.
public static int GetAge()
{
int age;
Console.Write("\nPlease input age > ");
while (!int.TryParse(Console.ReadLine(), out int age))
{
Console.Write("Invalid input. Please try again > ");
};
return age;
}
static void Main()
{
Console.WriteLine("\nPlease note\nThis program is only applicable for users born between 1999 and 2010");
string name = GetName();
string year = GetYear();
int age = GetAge();
}

Can C# decide what variable to assign a value to? [duplicate]

This question already has answers here:
Identify if a string is a number
(26 answers)
Closed 5 years ago.
Is there a way to write code so that when a user gives input, either a string or a number, that the program will choose the most appropriate of the available variables that have been declared?
Pseudocode example:
static void Main()
{
int A;
string B;
Console.Write("enter something: ");
if (user enters a number)
A = int.Parse(Console.ReadLine());
else
B = Console.ReadLine();
}

Simply said, since Console.ReadLine is the way to receive user input, and since it always returns a string, no matter what: No, you have to parse the string for being a number yourself, and in turn assign it to the most fitting variable yourself.
You can do that with int.TryParse, which returns true if the given string could be parsed into a (integral) number, assigned to the second out parameter in the same line:
static void Main()
{
Console.Write("enter something: ");
string B = Console.ReadLine();
if (int.TryParse(B, out int A))
Console.WriteLine($"Yay, user entered number {A}.");
else
Console.WriteLine($"Nay, user entered a boring string {B}.");
}

You can let int.TryParse() decide:
int A;
string B;
string userinput = Console.ReadLine();
// if parsing to int fails, assign to B
if (!int.TryParse(userinput, out A)
{
B = userinput;
}

Cannot implicitly convert type 'string' to 'int' (CS0029) [duplicate]

This question already has answers here:
Cannot implicitly convert type string to int
(4 answers)
Closed 8 years ago.
I'm on my way to learn C# by following the basic training tutorial from Lynda and trying to make some changes on their examples.
I'm stuck on an error that I can't find a solution for on Google.
Cannot implicitly convert type 'string' to 'int' (CS0029)
Code:
namespace l2
{
class Program
{
public static void Main(string[] args)
{
int arg;
arg = Console.ReadLine();
int result1;
result1 = formula(arg);
Console.WriteLine("the result is {0}",result1);
Console.ReadKey();
}
static int formula (int theVal){
return (theVal * 2 + 15);
}
}
}
I really don't understand why I get that error. My function is getting an int, the arg that I want to get from console is also an int. Where is the string that the compiler is talking about? :)

Console.ReadLine() returns a string.
What you want is
arg = int.Parse(Console.ReadLine());

The correct solution in this case will be.
string input;
input= Console.ReadLine();
int numberArg;
while (!int.TryParse(input, out numberArg))
{
Console.WriteLine(#"Wrong parameter. Type again.");
input= Console.ReadLine();
}
var result1 = formula(numberArg);
Console.WriteLine("the result is {0}", result1);
Console.ReadKey();

You could also attempt some subtle validation, by using the int.TryParse. Which will attempt to convert the value to an integer, if it indeed fails it will use the original value:
int id = 1;
int.TryParse("Hello", out id);
Console.WriteLine(id)
Output: 1
int id = 1;
int.TryParse("40", out id);
Console.WriteLine(id)
Output: 40
Also note that Console.ReadLine() will return a type of string. So to correctly solve your issue, you would do:
int arguement = 0;
while(!int.TryParse(Console.ReadLine(), out arguement)
{
Console.WriteLine(#"Error, invalid integer.");
Console.ReadLine();
}
So until they enter a valid integer they'll be trapped in the loop.

Cannot implicitly convert type 'string' to 'int [duplicate]

This question already has answers here:
How can I convert String to Int?
(31 answers)
Cannot implicitly convert type 'string' to 'int' error
(3 answers)
Closed 8 years ago.
I'm trying to write a program, and I want the program to read a line.
it is giving me this error
Cannot implicitly convert type 'string' to 'int
How can I convert the string to int? This is the part of the program that's giving the error.
class engineering : faculty
{
public engineering() \\constructor
{
}
public int maths_grade;
public override void fill_form()
{
Console.WriteLine("Insert Maths Grades: ");
int maths_grade = Console.ReadLine();
}
}

Try
int mathsGrade;
if (int.TryParse(Console.ReadLine(), out mathsGrade))
{
//Do something with grade
}
else
{
//Do something to warn of invalid input.
}

You should use:
int maths_grade = int.Parse(Console.ReadLine());
because ReadLine returns string, then you need to parse it to get int. But this will throw an exception if line won't contain valid string (number). You can better check this by using TryParse version:
string line = Console.ReadLine();
int maths_grade;
if (!int.TryParse(line, out maths_grade))
{
// Do some kind of error handling
}