calculation program and console.read() input stream

Question

is there's something wrong with my code below?

using System;
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int num1 = 0, num2 = 0, rslt = 0;
            char oprtr;

            Console.Write("Enter calculation: ");
            num1 = Convert.ToInt32(Console.Read());
            oprtr = Console.ReadKey().KeyChar;
            num2 = Convert.ToInt32(Console.Read());

            switch (oprtr)
            {
                case '+':
                    rslt = num1 + num2;
                    break;
                case '-':
                    rslt = num1 - num2;
                    break;
                case '*':
                    rslt = num1 * num2;
                    break;
                case '/':
                    rslt = num1 / num2;
                    break;
                default:
                    break;
            }
            Console.Write("rslt: {0}", rslt);
            Console.WriteLine();
            Console.ReadKey();
            return;
        }
    }
}

after i compile and run it, the result is 0

it looks like there's nothing wrong with my code.

don't know what's wrong with my code

You need to explain what the desired behavior of the program is. Without that, the question is off topic and should be closed. — Anders, Sep 06 '15 at 16:38

NASSER · Answer 1 · 2015-09-06T16:19:00.523

1

You need to use Console.ReadLine() instead of Console.Read(). Console.Read() reads the pressed key code not the value.

Replace the following lines

Console.Write("Enter calculation: ");
num1 = Convert.ToInt32(Console.Read());
oprtr = Console.ReadKey().KeyChar;
num2 = Convert.ToInt32(Console.Read());

with

Console.Write("Enter calculation");
Console.Write("\nEnter 1st Operand: ");
num1 = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter Operator: ");
oprtr = Console.ReadKey().KeyChar;
Console.Write("\nEnter 2nd Operand: ");
num2 = Convert.ToInt32(Console.ReadLine());

EDIT:

Use int.TryParse method to avoid exception because if user press any alphabet or special character then it cannot be store into integer.

Example

int num1;
if (!int.TryParse(Console.ReadLine(), out num1)
{
    Console.WriteLine("Invalid Number");
}
else
{
    //num1 is ready for calculations
}

Another thing, you should avoid integers because for division, integer/integer = integer, i-e 5/2 = 2 but it should 2.5

edited Sep 06 '15 at 16:19

answered Sep 06 '15 at 16:07

NASSER

5,900
7
38
57

in my program, i wanna use input like:7*8 so, i think `Console.ReadLine()` is not the right one. and also, press `ENTER` 3 time is very tedious, i guess... – chipp Sep 09 '15 at 09:19
hello? can anybody give me answer? – chipp Sep 13 '15 at 15:16
@chipp Probably you need [this](http://stackoverflow.com/questions/333737/c-sharp-evaluating-string-342-yield-int-18) because you want to solve `"7 * 8"` i-e string to expression. – NASSER Sep 13 '15 at 16:15
actually, i just want to use the input stream like it's done in C++: `int num1, num2;` `char sw;` `cin << num1 << sw << num2; //input 7+3` `cout >> sw; //print + on the screen` – chipp Sep 16 '15 at 08:29
i just wanna know how to extract `char` type from those sequential input like that – chipp Sep 16 '15 at 08:38
btw, how to write code in this site? i found this web is very fussy and complicating simple things like [code] tag -_- and even just to make a newline – chipp Sep 16 '15 at 08:41
@chipp Well, do you want to input just like `7+3` in single line, right? – NASSER Sep 18 '15 at 07:28
@chipp Can you input more than three operands? eg. `7+3+8` or `7-8*1`? – NASSER Sep 18 '15 at 07:28
Please let me know the ultimate inputs that user can input, then I will help you to achieve the output. :) – NASSER Sep 18 '15 at 07:30

calculation program and console.read() input stream

1 Answers1