I want to go back to the "Console.Write(num1), if use input the wrong value. how to code? Pls help!

Question

using System;

namespace ConsoleApp1
{
class Program
{
static void Main(string[] args)
{
do
{
Console.Write("num1 : ");
string str = Console.ReadLine();
if (str == "exit")
break;
int num1;
try
{
num1 = Convert.ToInt32(str);
}
// I want to go back to start after catch {}, how to do.
catch
{
Console.WriteLine("You are keying in the wrong value, Please Try Again");
num1 = 0;
}

Console.Write("num2 :");
int mum2 = Convert.ToInt32(Console.ReadLine());

//sum of num1 and mum2

int sum = num1 + mum2;
Console.WriteLine("Result: {0}" ,sum);

Console.WriteLine("\nThat is amazing");
Console.Read();

} while (true);
}
}
}

Answer 1

You can add 'continue' as the last statement in the catch clause and you will go back to the start of the do...while loop.

Instead of using try...catch for checking if input is integer number you can use int.TryParse method.

Answer 2

Thank you for help

Answer 3

To achieve that you could do something like this:

using System;

namespace ConsoleApp1
{
class Program
{
static void Main(string[] args)
{
string wrongInputInfo = "You are keying in the wrong value, Please Try Again";
bool exit = false;

do
{
Console.Write("num1: ");
string str = Console.ReadLine();

int num1;

while (!int.TryParse(str, out num1))
{
if (IsExit(str))
{
exit = true;
break;
}

Console.WriteLine(wrongInputInfo);
Console.Write("num1: ");
str = Console.ReadLine();
}

if (exit)
break;

Console.Write("num2: ");
int num2;

str = Console.ReadLine();

while (!int.TryParse(str, out num2))
{
if (IsExit(str))
{
exit = true;
break;
}

Console.WriteLine(wrongInputInfo);
Console.Write("num2: ");
str = Console.ReadLine();
}

if (exit)
break;

//sum of num1 and mum2

int sum = num1 + num2;
Console.WriteLine("Result: {0}", sum);

Console.WriteLine("\nThat is amazing");
Console.ReadLine();

} while (true);
}

static bool IsExit(string input)
{
if (input == "exit")
return true;

return false;
}
}
}

Answer 4

Can you please write some sample code for Try.Parse() Method?

If user inputs wrong in num2, I want to go back to "Console.Write("num2 : "). How to code.

Thanks!

Answer 5

Thanks you so much.