For loop working in C# [closed] - c#

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I am writing a program that finds the number of 1's in an array.. but the "scanning" inside the "for" loop takes place only once.
for (i = 0; i < 11; i++ )
{
k = Convert.ToInt32(Console.Read());
if (k==1)
{
ans++;
}
// Console.WriteLine("i == {0}", i);
}
Is this normal in C# or am I doing something wrong? I tried to search for this problem but cannot find any answers!

Do
Console.ReadLine()
instead of
Console.Read()
When you reach the first Console.Read() the inputstream is saved but only the first character is returned by the Read method. Subsequent calls to the Read method retrieve your input one character at a time from the inputstream.
Ex:
First iteration:
k = Console.Read(); //you input "abc1", k = a
Second iteration:
k = Console.Read(); // k = b
and so on.
When the last character in the inputstream is returned, the next call to Console.Read() will display the console again so you can input a new string and hit Enter.
Console.Read() docu

There's no array in your code, actually. Personally I'd rewrite this to:
string input = Console.ReadLine();
for (i = 0; i < input.Length; i++ )
{
int k = Convert.ToInt32(input.Substring(i, 1));
if (k==1)
{
ans++;
}
}
Which lets the user enter a string first and then does all the parsing. Of course, the user may enter more or less than exactly 11 characters in this code, so if you really need 11 numbers, I'd add extra messages and checks.
Also this code (as your original code) fail miserably if the user enters something non-numeric, so exception handling would be on the task list as well.

Try to use this code, I think it will answer your problem
string[] sample = { "1", "1", "3" };
var a = (from w in sample
where w == "1"
select w).ToList();
Console.Write(a.Count);

Related

Splitting numbers into list/array (e.g. 1998 to 1,9,9,8) [closed]

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this is my first post so excuse me if I am not being clear enough.
As the title says I want to split a number into smaller parts, for example 1998 to 1,9,9,8. I have looked around but I am stuck trying to figure out the right term to search for.
Reason why I want this done is to later multiply every other number with either 1 or 2 to be able to examine whether it's correct or not.
Sorry I can't provide any code because I am not sure how I should tackle this problem.
As #mjwills said, mod is what you want.
static IEnumerable<int> Digitize(int num)
{
while (num > 0)
{
int digit = num % 10;
yield return digit;
num = num / 10;
}
}
And then call it like so:
static void Main(string[] _)
{
int num = 1998;
int[] digits = Digitize(num).ToArray();
Console.WriteLine($"Original: {num}");
foreach (var digit in digits)
Console.WriteLine(digit);
}
make a string of that number and make it like this
```
int a = 1990;
int[] intArray = new int[a.ToString().Length];
int index = 0;
foreach( char ch in a.ToString())
{
intArray[index] = int.Parse(ch.ToString());
index++;
}

Master mind in console [closed]

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I want to make some sort of mastermind game in the console where the computer generates a 3 digit code and you have to guess it. The computers also tells you which digit you get right after you take a guess. How would i best do this? I don't know a way to "chop up" input so that i can make the computer check it against the digit it has.
example:
computer generates random code: 123
you guess: 321
computer : -*- (the star indicates which digit you got right)
I have an idea about how i'd indicate what digits are right or not, but i don't know how to separate the input into parts
Convert the computer generated random number into a string. The user input is given as string anyway.
The string type has an indexer allowing you to access single characters
string s = "abc";
char a = s[0];
char b = s[1];
char c = s[2];
for (int i = 0; i < s.Length; i++) {
Console.WriteLine($"s[{i}] = '{s[i]}'");
}
You write char literals as
char ch = 'x';
using single quotes.
Example:
string userInput = Console.ReadLine();
int code = SomehowGenerateRandomCode();
string codeString = code.ToString();
// Let's assume that both numbers have 3 digits.
for (int i = 0; i < 3; i++) {
if(userInput[i] == codeString[i]) {
// digits are equal
} else {
// digits are different
}
}
To split an int to its digits you can convert to string an split like:
int i = 123;
string myInt = i.ToString();
List<int> digits =new List<int>();
foreach (char c in myInt)
{
digits.Add(int.Parse(c.ToString());
}

String vector with user input [closed]

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Stuck for hours on this task. I really appreciate help, it is not shown in the literature how this is to be done. I can create the vector but after that I'm totally blocked.
Create a string vector with five elements. The user will then enter 5 names via a for loop. The program then writes these names via another for loop.
Please type out the code so I can understand. Without solving this first task I can't do the other ones.
Here's my futile attempt so far
int [] namn = new int [5];
for (int i = 0; i < 5; i++);
{
Console.Write("Ange fem namn");
string str = Console.ReadLine();
int names = Convert.ToInt32(str);
}
It seems that the main (and the most difficult error to find) is ; after for loop
for (int i = 0; i < 5; i++);
this loop does nothing five times.
//DONE: "string[]" - Create a STRING vector with five elements...
string [] namn = new string [5];
//DONE: namn.Length - no magic numbers (5)
for (int i = 0; i < namn.Length; i++) // !!! no ";" !!!
{
Console.Write("Ange fem namn");
//DONE: put into array, not to a local variable
namn[i] = Console.ReadLine();
}
// Print out the names
foreach(var item in namn)
Console.WriteLine(item);

How do you loop Readline statements? [closed]

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I have a homework assignment and I am stuck on a certain part of the question.
How do I loop numbers regarding the readline statement.
In other words, suppose I have two numbers that I want to input. Instead of typing out the readline statement twice, how do I get a loop that would allow me to type the readline statement once?
have two numbers that I want to input. Instead of typing out the readline statement twice, how do I get a loop that would allow me to type the readline statement once
Well, if you want two numbers, then you're going to need two variables (or an array), so I assume you're trying to change this:
int firstNumber;
int secondNumber;
firstNumber = int.Parse(Console.ReadLine());
secondNumber = int.Parse(Console.ReadLine());
into something like this:
int[] myNumbers = new int[2];
for(int i = 0; i < 2; i++)
{
myNumbers[i] = int.Parse(Console.ReadLine());
}
but think about this:
Will the prompt be the same for both numbers? Or will the prompt change between inputs
Is it easier to assess the variables independently versus a part of the array/list?
Will having the numbers in a structure benefit other parts of my app (looping to get a sum, etc.)
I think a loop as fine so long as you don't end up with logic inside the lop that changes depending on which number you're using:
int[] myNumbers = new int[2];
for(int i = 0; i < 2; i++)
{
if i == 0 // bad
string prompt = "Enter the first number";
else
string prompt = "Enter the second number";
Console.WriteLine(prompt);
myNumbers[i] = int.Parse(Console.ReadLine());
}
int[] myInputs = new int[2];
for(int i=0; i < 2; ++i)
{
myInputs[i] = Int32.Parse(Console.ReadLine());
}
After this, myInputs[0] is the first value, and myInputs[1] is the second value.

Grid of numbers that randomizes on click [closed]

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I'm making a game that involves finding and clicking on a number (0-9) in a grid that randomizes each time you click on the correct one.
I want to get it so that when you click on the correct number, the grid randomizes again.
How would you do this?
Here's what it would kind of look like in the end:
I assume you're rendering an array of integers in order:
for (int i = 0; i < arrayOfNumbers.Length; i++ ) {
// rendering here
render(arrayOfNumbers[i]);
}
If thats the case.. just randomize the array after a successful click.. somewhat like this:
var rnd = new System.Random();
var arrayOfNumbers = Enumerable.Range(1, 9).OrderBy(r => rnd.Next()).ToArray();
Then you can just re-render (or let your game loop continue to render the array). Since the array has changed, your rendering will too.
Every time you detect a click on the correct number (I hope you know how to do this) you simply randomize the array of numbers you're displaying in your grid:
//Fisher-Yates algorithm
Random generator = new System.Random();
int len = array.Length;
while (len > 1)
{
len--;
int k = generator.Next(len + 1);
int temp = array[k];
array[k] = array[len];
array[len] = temp;
}

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