Attempting to convert a string to an int (C#) - c#

I'm trying to learn the basics to c# coding (or any code for that matter). I'm not understanding how to take user input and put it into a string that I can later use as an integer. I thought I could write it like
string baseOfTriange = int.Parse(Console.ReadLine));
but it's not working. I've also tried float thinking maybe that was it, however, I'm just lost on the concept. This is what I have so far, I just can't figure out how to convert a string to an int. Thanks for any help.
static void Main(string[] args)
{
// area of a triangle = base(height)/2
Console.WriteLine("Welcome, enter your triangle dimensions. ");
Console.WriteLine();
Console.Write("What is the base of the triangle? ");
string baseOfTriangle = int.Parse(Console.ReadLine());
Console.WriteLine("You answered, " + baseOfTriangle + ". ");
Console.Write("What is your height of the triangle? ");
string heightOfTriangle = int.Parse(Console.ReadLine());
Console.WriteLine("You answered, " + heightOfTriangle + ". ");
Console.WriteLine("The area of the triangle is " + (baseOfTriangle * heightOfTriangle / 2));
Console.ReadLine();
}

I'll assume you're getting a compile time error because of the following line:
string baseOfTriangle = int.Parse(Console.ReadLine());
The return type of int.Parse is int but your trying to assign it to a variable of type string. Change the type of baseOfTriangle and heightOfTriangle to int and that will solve your problem.
int baseOfTriangle = int.Parse(Console.ReadLine());
^^^
Also, you probably want a floating point answer. Otherwise 1*1/2 will give you an answer of 0. Change it to baseOfTriangle * heightOfTriangle / 2.0. Or better yet use double and double.Parse.

Take a look at the C# Programming Guide: How to: Convert a String to a Number:
http://msdn.microsoft.com/en-us/library/bb397679.aspx
Also look at the TryParse methods for most built-in number types for c#. For example, int32.TryParse():
http://msdn.microsoft.com/en-us/library/system.int32.tryparse(v=vs.110).aspx

static void Main(string[] args)
{
Console.Write("What is the base of the triangle? ");
int baseOfTriangle = int.Parse(Console.ReadLine());
Console.Write("What is your height of the triangle? ");
int heightOfTriangle = int.Parse(Console.ReadLine());
Console.WriteLine("The area of the triangle is {0}", (baseOfTriangle * heightOfTriangle) / 2);
Console.ReadLine();
}

The usual method to convert to int is with Convert.ToInt32()

Related

How to multiply correctly two numbers in a method?

{
Console.ForegroundColor= ConsoleColor.Yellow;
Console.BackgroundColor = ConsoleColor.DarkRed;
Console.Clear();
Console.WriteLine("Please enter your name and I will tell you how many letters your name has!");
string name = Console.ReadLine();
Count(name);
Console.WriteLine("Now tell me two numbers and I will multiply them!");
Console.Read();
try
{
Multiply();
}
catch (FormatException)
{
Console.WriteLine("You must enter a number!");
}
}
public static void Count(string name)
{
Console.WriteLine("Your name has {0} letters!", name.Length);
}
public static void Multiply()
{
string firstNum = Console.ReadLine();
string secondNum = Console.ReadLine();
int num = Int32.Parse(firstNum);
int num1 = Int32.Parse(secondNum);
int result = num * num1;
Console.WriteLine("The result is {0}", result);
}
Im a beginner and Im learning about methods so I made this simple code where the user should enter two numbers and I should multiply them, the problem is, whenever I enter two random numbers, I am getting some completely different numbers back no matter if i want to add them, multiply them or something third.
I cannot figure out why the "num1 * num2;" is not giving me a correct number. E.G. 54*19 should give me 1026, but instead its giving me -15.
you need to comment on the Console.Read(); line. this is the main cause.
I have run your code by commenting on the above line and it works as expected for me
Also, you need to handle the scenarios when the user can enter a non-integer input, so you could use int.TryParse for the same.
Also, try to handle the scenario where the integer value is very large and the multiplication of two numbers exceeds the integer max value.

C# console app finishing with code 0 instead of providing the output it's supposed to calculate

The program is supposed to calculate compound interest by getting several inputs from the user and then applying those with the compound interest formula, however while gramatically correct, the program does everything correctly except for ouputting the calculated value. Any ideas why this might be happening?
using System;
namespace compoundCalc
{
class Program
{
static void Main(string[] args)
{
Console.Write("Enter investment sum:");
int investment = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter annual interest rate:");
double interestRate = Convert.ToDouble(Console.ReadLine());
Console.Write("Enter the number of times per year that interest is compounded per period:");
int compoundNumber = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter the number of periods the money is invested for:");
int investmentPeriod = Convert.ToInt32(Console.ReadLine());
double nt = Math.Pow((compoundNumber * investmentPeriod),(1+interestRate / compoundNumber ));
double futureCapital = investment * nt;
Console.WriteLine("The future value of your investment is:", Convert.ToString(futureCapital));
}
}
}
Console.WriteLine(String, Object) method signature requires the string include a format character, which you don't have.
If you want to use String interpolation, then that would look like
Console.WriteLine($"The future value of your investment is: {futureCapital}");
You need to tell the Console where to display the futureCapital add this {0} to last of your string
Console.WriteLine("The future value of your investment is: {0}",Convert.ToString(futureCapital));
or you can use string concatenation +
Console.WriteLine("The future value of your investment is: " + futureCapital);
or more convenient use string interpolation $
Console.WriteLine($"The future value of your investment is:{futureCapital}");

C# console application - Calculating an average number

I tried to create a program which would give me an average score of 5 tests. First I created 5 variables that would be declared by an user. But I have a problem that I could not fix by myself. The output of my code shows a false average score of tests, probably I have a mistake somewhere and I would like you to help me in finding it.
Here is a full code:
using System;
namespace Test
{
class MathTest
{
static void Main()
{
string a, b, c, d, e;
Console.WriteLine("1st Test Score: ");
a = Console.ReadLine();
Console.WriteLine("2nd Test Score: ");
b = Console.ReadLine();
Console.WriteLine("3rd Test Score: ");
c = Console.ReadLine();
Console.WriteLine("4th Test Score: ");
d = Console.ReadLine();
Console.WriteLine("5th Test Score: ");
e = Console.ReadLine();
Console.WriteLine("Your Average Test Score is: {0}",
Convert.ToInt32(a + b + c + d + e) / 5);
}
}
}
Hopefully there is only one mistake in the last sentence, the formula. Thanks for your attention.
As others have correctly said, you need to convert the strings to numbers first, then add them, and then divide them.
That fixes some of your problems. However, not all your problems are over yet.
Next: what if someone types in a score of 75.5 ? Teachers sometimes give half points. Integer is not the correct data type. In C#, use decimal for quantities that are exact decimal quantities, and double for quantities that are physical amounts, like length or mass. You should convert all the strings to decimal, not int.
Next: what if someone types in "Hello" or nothing at all, instead of a number? Your program will crash. You need to use a method such as TryParse that detects this situation, and then you need to prompt the user accordingly to re-enter the number correctly.
Now, you should not be rewriting all that code five times over. Make a method which prompts the user in a loop to enter a number, and returns that number when they do so successfully. Always be breaking your problem down into smaller problems and then write a method which solves that problem. That way your main routine stays simple even when your program logic gets complicated.
Finally and most important: today is a good day to learn how to use a debugger. Learn how to find problems like this on your own, rather than asking strangers on the internet to do your work for you. Most of computer programming is debugging, so learn that skill now.
You should Convert.ToInt32 each item (a..e):
...
Console.WriteLine("Your Average Test Score is: {0}",
(Convert.ToInt32(a) +
Convert.ToInt32(b) +
Convert.ToInt32(c) +
Convert.ToInt32(d) +
Convert.ToInt32(e)) / 5.0);
Another (possible) problem is integer division: if you want to have floating point result (e.g. average score 3.5) you should divide by 5.0, not 5
You're concatenating strings first, then casting the result to Int and dividing by 5.
Cast every number first, before doing maths on them.
You are converting the concatenated string. Suppose the user enters:
1
2
3
4
5
Then (a+b+c+d+e) is "12345" and you are calculating 12345/5. You need to cast all strings separately first.
You have to convert before you Sum up.
Console.WriteLine("Your Average Test Score is: {0}", (Convert.ToInt32(a) + Convert.ToInt32(b) + Convert.ToInt32(c) + Convert.ToInt32(d) + Convert.ToInt32(e)/5)
Well, I found out my mistake in the comments and answers and fixed the code (Changed only a mid part)
int a, b, c, d, e;
Console.WriteLine("1st Test Score: ");
a = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("2nd Test Score: ");
b = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("3rd Test Score: ");
c = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("4th Test Score: ");
d = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("5th Test Score: ");
e = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Your Average Test Score is: {0}", Convert.ToInt32(a + b + c + d + e) / 5.0);

Code won't give desired output or read second input

Sorry if this isn't the right. This is my first time posting here. I'm a first year Software student and for the life of me i cannot seem to get this to work. I know its something simple I'm missing but oh well. I tried doing this using methods but again no help. Maybe you guys could help me?
The problem is the code wont let me input after the "Are you a member (Y/N)" writline statement and just keeps giving me an output of 50.
static void Main(string[] args)
{
//Local Variable Declaration//
double rate1 = 10;
double rate2 = 3;
double maxCharge = 50;
double charge;
Console.WriteLine("Enter number of hours (-999 to quit) : ");
int hoursRented = Console.Read();
if (hoursRented >= 3)
{
charge = hoursRented * rate1;
}
else
{
charge = (3 * rate1) + (hoursRented * rate2);
}
if (charge > maxCharge)
{
charge = maxCharge;
}
Console.WriteLine("Are you a member? (Y/N) : ");
int memberStatus = Console.Read();
if (memberStatus.Equals("Y"))
{
charge = (charge * 1 / 10) - charge;
}
Console.WriteLine("Customer Charge : {0} Total Charge To Date : ", charge);
}
The problematic lines are below
Console.WriteLine("Enter number of hours (-999 to quit) : ");
int hoursRented = Console.Read();
if (hoursRented >= 3) {
and
Console.WriteLine("Are you a member? (Y/N) : ");
int memberStatus = Console.Read();
if (memberStatus.Equals("Y")) {
When you call Console.Read(), it reads only characters and returns it as an int. You seem to mistakenly think it will parse the character to an int.
Secondly, think what happens when you provide multiple characters as input to a single Console.Read() call. Interestingly, the remaining characters are read in the subsequent calls. So when you type any number followed by Enter in the first Console.Read it only, reads the first character, the subsequent characters, including the EOLN char are returned in the subsequent calls, instead of prompting you to enter information for the next call.
The fix is easy. Use Console.Readline() and int.parse (or its int.TryParse() variant
Then the corresponding code will look like below
Console.Write("Enter number of hours (-999 to quit) : ");
string hoursRentedStr = Console.ReadLine();
int hoursRented = int.Parse(hoursRentedStr);
if (hoursRented >= 3) {
and
Console.Write("Are you a member? (Y/N) : ");
string memberStatus = Console.ReadLine();
if (memberStatus.Equals("Y")) {
This is because you are just writing:
Console.WriteLine("Are you a member? (Y/N) : ");
and continuing through.
you must do it like this:
Console.WriteLine("Are you a member? (Y/N) : ");
Console.ReadLine();
and then:
int memberStatus = Int.Parse(Console.ReadKey());
your problem is that your are using Console.Read wich returns the ascii code of the next charachter as said by #juharr in the comments. so the solution is too simply replace Read By ReadLine and change your code like this, so that ReadLine wich is a string will be converted to the int value that you want
int hoursRented = int.Parse(Console.ReadLine());
And change your member status to a string to compare it with "Y" easily
string memberStatus = Console.ReadLine();
Note: if you want to validate the input you should use a int.TryParse instead of just a normal parse like I used as it returns a bool so you knows when it fails

How to take user input in the same line?

I'm bigener in C# programming
So, I was just wondering about how to take user input in the same line?
this is my code and also I want to print the output in the same line
using System;
namespace Wa2
{
class BodyMassCalculation
{
public static void Main (string[] args)
{
Console.WriteLine ("BMI Calculator\n");
double weight;
Console.WriteLine ("Enter your weight in kilograms: ");
weight = Convert.ToInt16(Console.ReadLine());
double height;
Console.WriteLine ("Enter your height in centimetres: ");
height = Convert.ToInt16(Console.ReadLine());
double meter;
meter = height / 100;
Double BMI;
BMI = (weight) / (meter*meter);
Console.WriteLine ("Your BMI is " , BMI);
Console.WriteLine(BMI.ToString("00.00"));
}
}
}
Try this:
Console.Write("Enter your input here: ");
string userinput = Console.ReadLine();
Just change Console.WriteLine to Console.Write.
Use Console.Write() instead of Console.WriteLine().
I think that's what you mean anyway, the question isn't very clear.
I think you're asking if it's possible to read both height and weight at the same time:
// C equivalent
printf ("Enter height (cm) and weight (kg): ");
scanf ("%d %d\n", &h, &w);
Yes, there are several alternatives.
Arguably the easiest is use Console.ReadLine() (like you're doing) and parse the string.
You can also try multiple "Console.Read()" (one for each argument).

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