using System;
namespace reverse
{
class Program
{
static void Main(string[] args)
{
int[] a = new int [10];
for (int i= 0; i<a.Length; i++)
{
a[i] = int.Parse(Console.ReadLine());
}
}
}
}
here I can get values from a user by pressing enter key after each time i give the value but I want to give value as a whole with comma. Thanks!
I would suggest to gradually step towards functional programming.
Why?
Weel, with words from Eric Lippert from "Functional programming for beginners"
I will talk about the “why” a little bit, but basically it boils down to
a great many bugs are caused by bad mutations.
By taking a page
from functional style and designing programs so that variables and
data structures change as little as possible, we can eliminate a
large source of bugs.
Structuring programs into small functions
whose outputs each depend solely on inputs
makes for programs that
are easy to unit test.
the ability to pass functions as data
allows us to create new and interesting control flows and patterns,
like LINQ.
Rewriting your code
Use Linq in a single and simple line:
int [] res =
Console.ReadLine () // read the input
.Split (',') // transform it into an array
.Take (10) // consider only the first 10 strings
.Select (int.Parse) // transform them into int
.ToArray (); // and finally get an array
You can add a check after the Split and before Take:
.Where (d => {int t; return int.TryParse (d, out t);}).Take
Try this one and read comments to get more info :
static void Main()
{
string input = Console.ReadLine(); // grab user input in one whole line
string[] splitted = input.Split(','); // split user input by comma sign ( , )
int[] a = new int[splitted.Length]; // create a new array that matches user input values length
for(int i = 0; i < splitted.Length; i++) // iterate through all user input values
{
int temp = -1; // create temporary field to hold result
int.TryParse(splitted[i], out temp); // check if user inpu value can be parsed into int
a[i] = temp; // assign parsed int value
}
}
This method will ensure that program will execute even if user wont input numerics. For example if user input will be :
1 , 2,3,45,8,9898
The output will be :
{ 1, 2, 3, 45, 8, 9898 }
But if the input will be :
1,adsadsa,13,4,6,dsd
The output will be :
{ 1, 0, 13, 4, 6, 0 }
Related
I'm using c#, I have a string of cash entries I need to add together and get the total
arrTotalSplitCosts.Text = "24.90,10.60,1.90,20";
While the below works, as soon as I add a decimal point or a string value to replace the numbers in the array with my generated numbers, the below crashes
int[] arr = new int[] { 1, 2, 3 };
int sum = 0;
for (int i = 0; i < arr.Length; i++)
{
sum += arr[i];
}
I want to take these values from a form post:
arrTotalSplitCosts.Text = "24.90,10.60,1.90,20";
And total them e.g. Total = 57.40
Anyone got any ideas, I'm struggling, thanks in advance.
The input is a string (not an array of string, but a single string).
You then have to take that string and split it into a list or array.
The values have decimals, so they cannot be dealt with as int. int is an integer; a whole number. You should deal with your data as a list of doubles.
When you convert from string to double, you should use tryparse, as you can more stringently enforce the conversion and check for exceptions as you go.
I've put a sample below, but note that I made it much more verbose than I normally would, just to (hopefully) more clearly show each of the steps.
If I was going to actually do this, I would use Linq more and combine multiple steps into single lines.
So something like this:
using System;
using System.Collections.Generic;
using System.Linq;
public class Program
{
public static void Main()
{
Console.WriteLine("Hello World");
var inString = "24.90,10.60,1.90,20";
var stringValues = inString.Split(',');
List<double> doubleValues = new List<double>();
foreach(string v in stringValues){
double outNum;
double num = double.TryParse(v, out outNum)? outNum : 0;
doubleValues.Add(num);
}
Console.WriteLine(doubleValues.Sum(i => i)); // output = 57.4
}
}
Don't use , as a seperator. You can prefer ;.
For 10.000,00 formatting style
var sum = arrTotalSplitCosts.Text.Split(';').Select(decimal.Parse).Sum()
For 10,000.00 formatting style
var sum = arrTotalSplitCosts.Split(';').Select(a => decimal.Parse(a, CultureInfo.InvariantCulture)).Sum()
I´m working on some codes in C# for school. But there is this exercise that is huge headache.
This is it: I have to develope a code that allows the user to set a value (put in an x) for a 2D array (5x5) from the keyboard. This means that when running the program the user should be able to set one value inside the array, something like "I wana set an "x" in 2,5 and 3,1". I just have no clue how to do that. it´s been already two weeks but i can´t figure it out.
This is what i have so far (updated, thnx to all, specially BradleyDotNET for support):
int[,] data = new int[5, 5];
public void load()
{
string[] input = Console.ReadLine().Split('=');
string[] coordinates = input[0].Split(',');
int[] intCoordinates = coordinates.Select(s => int.Parse(s)).ToArray();
data[intCoordinates[0]][intCoordinates[1]] = int.Parse(input[1]);
}
public void view()
{
Console.WriteLine("Matrix created is:");
for (int i = 0; i <= 4; i++)
{
Console.Write("\n");
for (int j = 0; j <= 4; j++)
{
Console.Write(data);
}
}
Console.ReadKey();
}
static void Main(string[] args)
{
Program objeto = new Program();
objeto.load();
objeto.view();
Console.ReadKey();
Console.Clear();
I also have to add a feature to let the user add as many "x" to the matriz as he wants, but im planning to do that with a "switch".
So, How do you set values inside the 2d array from keyboard?
Update: The mistake i get here is in line 10, inside "data". It says "Incorrect index number inside []. 2 was expected"
You didn't specify the format the input, so I"ll make one up. If the input was "2,4=10" (meaning set element[2][4] to 10), the code would be:
string[] input = Console.ReadLine().Split('=');
string[] coordinates = input[0].Split(',');
int[] intCoordinates = coordinates.Select(s => int.Parse(s)).ToArray();
matrix[intCoordinates [0]][intCoordinates [1]] = int.Parse(input[1]);
This code has a few problems with it, there is no range validation and if the user enters anything other than an int, it will throw. I'll leave those as an exercise to you, but feel free to ask if you run into trouble.
To explain, we use Console.ReadLine to get a whole line of input. Then we break it on the '=' character to get our coordinates and desired value. We then split the coordinates on ',' to get the different indices.
You can't use strings as array indices, so we call Select to invoke the int.Parse() function on each string, returning us a new array of ints.
Finally, we use the parsed indices to index into matrix and set it to the parsed value from the input.
Something like this should help you.
public void load()
{
for (int i = 0; i <= 4; i++)
{
for (int j = 0; j <= 4; j++)
{
Console.WriteLine("enter value for {0},{1}", i, j);
matrix[i,j]= int.Parse(Console.ReadLine());
}
}
}
BTW, in your view method start the loop from 0 to 4
I have a series of incorrectly encoded base36 values - these were encoded from integers using a string of letters, missing the "i" and "o". They now need to be converted back to integers using C#.
There are multiple permutations because of the rollover effect.
"0" can either equal 0 or 34;
"1" can either equal 1 or 35.
So, for instance, if I have a string "a110", it has six possible values.
I'm having a hard time trying to figure how to code for this.
All the examples I've looked at compute variations for a set of elements, for example
char[] = { a, b, c }
int[] = { 1, 2, 3 }
However, in my case, there are conditionals involved too, and it's making my head hurt. Can anyone help?
You can compute the list of all possible input strings. First, read the input into a list of ints. Now, you know that each of those (if it's a sufficiently low value) could be one of two things. So then you can create an enumerator that returns all of the possible inputs, via a recursive descent.
I managed to do it with the following code. It was actually a little simpler than I expected, since I only had two conditions, and two options. It uses recursion and steps through each character in the string. If that character is a 0 or 1, it then diverges, and continues building the string.
It actually generates a few duplicates, so I had to add a condition to only add it to the string list if it doesn't already exist. If someone else can point me to slightly better logic I'd appreciate it
public string st = "101"; // hardcoded for now
public char[] cs;
public List<string> variations;
static void Main()
{
cs = st.ToCharArray();
variations = new List<string>();
vary("",0);
}
static void vary(string m, int n)
{
for (int i = n; i < cs.Count(); i++)
{
if (cs[i] == '0' || cs[i] == '1')
{
// recurse
combo(m + (cs[i] == '0' ? "0" : "1"), i + 1);
combo(m + (cs[i] == '0' ? "Y" : "Z"), i + 1);
}
m += cs[i];
}
if(!variations.Contains(m))
variations.Add(m);
}
for the string "101" I get the following combinations
101
10Z
1Y1
1YZ
Z01
Z0Z
ZY1
ZYZ
Thanks for the help with my question about making an array of booleans into a string. The code is now working good. Now I have another problem. Maybe somebody would like to try. I think I could come up with a solution but if so I'm 99 percent sure that it would be not so simple as the answers I have seen from people here.
What I have is the string "ABD" from my question here. I also have an array of integers. For example [0] = 2, [1] = 3 and [2] = 1. I would like to find a way to apply this to my string to reorder the string so that the string changes to BDA.
Can anyone think of a simple way to do this?
If those integers are 1-based indices within the string (i.e. 2 = 2nd character), then you could do this:
string s = "ABD";
int[] oneBasedIndices = new [] { 2, 3, 1 };
string result = String.Join(String.Empty, oneBasedIndices.Select(i => s[i-1]));
NB: If you are using a version less than C# 4.0, you need to put a .ToArray() on the end of the select.
What this is doing is going through your int[] and with each int element picking the character in the string at that position (well -1, as the first index in an array is 0, but your example starts at 1).
Then, it has to do a String.Join() to turn that collection of characters back into a String.
As an aside, I'd recommend downloading LINQPad (no connection) - then you can just paste that code in there as a C# Program, and at any point type variable.Dump(); (e.g. result.Dump(); at the end) and see what the value is at that point.
First make a copy of the string. The copy will never change; it serves as your reference to what the values used to be.
Then loop through the original string one character at a time using a for loop. The counter in the for loop is the position of which character in the original string we are replacing next. The counter is also the index into the array to look up the position in the original string. Then replace the character at that position in the original string with the character from the copied string.
string orig = "ABD";
int[] oneBasedIndices = new [] { 2, 3, 1 };
string copy = orig;
for ( int i = 0; i < orig.Length; i++ )
{
orig[i] = copy[ oneBasedIndices[i] - 1 ];
}
There you have it. If the indices are zero based, remove the - 1.
Napkin code again...
string result = "ABD"; // from last question
var indecies = new []{ 1,2,0 };
string result2 = indecies.Aggregate(new StringBuilder(),
(sb, i)=>sb.Append(result[i]))
.ToString();
or a different version (in hopes of redeeming myself for -1)
StringBuilder sb = new StringBuilder();
for(int i = 0; i < indecies.Length; i++)
{
sb.Append(result[i]); // make [i-1] if indecies are 1 based.
}
string result3 = sb.ToString();
i'm quite a beginner in C# , i tried to write a program that extract words from an entered string, the user has to enter a minimum length for the word to filter the words output ... my code doesn't look good or intuitive, i used two arrays countStr to store words , countArr to store word length corresponding to each word .. but the problem is i need to use hashtables instead of those two arrays , because both of their sizes are depending on the string length that the user enter , i think that's not too safe for the memory or something ?
here's my humble code , again i'm trying to replace those two arrays with one hashtable , how can this be done ?
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;
namespace ConsoleApplication2
{
class Program
{
static void Main(string[] args)
{
int i = 0 ;
int j = 0;
string myString = "";
int counter = 0;
int detCounter = 0;
myString = Console.ReadLine();
string[] countStr = new string[myString.Length];
int[] countArr = new int[myString.Length];
Console.Write("Enter minimum word length:");
detCounter = int.Parse(Console.ReadLine());
for (i = 0; i < myString.Length; i++)
{
if (myString[i] != ' ')
{
counter++;
countStr[j] += myString[i];
}
else
{
countArr[j] = counter;
counter = 0;
j++;
}
}
if (i == myString.Length)
{
countArr[j] = counter;
}
for (i = 0; i < myString.Length ; i++)
{
if (detCounter <= countArr[i])
{
Console.WriteLine(countStr[i]);
}
}
Console.ReadLine();
}
}
}
You're not doing too badly for a first attempt but this could be a lot better.
First thing: use TryParse rather than Parse when parsing an integer input by a human. If the human types in "HELLO" instead of an integer, your program will crash if you use Parse; only use Parse when you know that it is an integer.
Next thing: consider using String.Split to split the string into an array of words, and then process the array of words.
Next thing: code like yours that has a whole lot of array mutations is hard to read and understand. Consider characterizing your problem as a query. What are you trying to ask? I'm not sure I completely understand your code but it sounds to me like you are trying to say "take this string of words separated by spaces. Take a minimum length. Give me all the words in that string which are more than the minimum length." Yes?
In that case, write the code that looks like that:
string sentence = whatever;
int minimum = whatever;
var words = sentence.Split(' ');
var longWords = from word in words
where word.Length >= minimum
select word;
foreach(var longWord in longWords)
Console.WriteLine(longWord);
And there you go. Notice how the code reads like what it is doing. Try to write code so that the code conveys the meaning of the code, not the mechanism of the code.
One word. Dictioary (or HashTable). Both are standard datatypes you can use
Use a Dictionary for this (in your case, you are looking for a Dictionary).
Your extracted string will be the key, the length of it the Value.
Dictionary<string, int> words = new Dictionary<string,int>();
//algorithm
words.Add(word, length);