I found this code that i need for an assigment, but it only reads odd numbers and i need it to read even numbers too, but i don't know whats wrong. I need it to make the random magic squares go from 1 to 10.
Still very much a beginner and don't understand functions yet, please let me know if there is a way to dolve this.
using System;
class GFG
{
// Function to generate odd sized magic squares
static void generateSquare(int n)
{
int[,] magicSquare = new int[n, n];
// Initialize position for 1
int i = n / 2;
int j = n - 1;
// One by one put all values in magic square
for (int num = 1; num <= n * n;)
{
if (i == -1 && j == n) // 3rd condition
{
j = n - 2;
i = 0;
}
else
{
// 1st condition helper if next number
// goes to out of square's right side
if (j == n)
j = 0;
// 1st condition helper if next number is
// goes to out of square's upper side
if (i < 0)
i = n - 1;
}
// 2nd condition
if (magicSquare[i, j] != 0)
{
j -= 2;
i++;
continue;
}
else
// set number
magicSquare[i, j] = num++;
// 1st condition
j++;
i--;
}
// print magic square
Console.WriteLine("The Magic Square for " + n
+ ":");
Console.WriteLine("Sum of each row or column "
+ n * (n * n + 1) / 2 + ":");
for (i = 0; i < n; i++)
{
for (j = 0; j < n; j++)
Console.Write(magicSquare[i, j] + " ");
Console.WriteLine();
}
}
// driver program
public static void Main()
{
Console.WriteLine("Value of n: ");
int n = int.Parse(Console.ReadLine());
// Works only when n is odd
generateSquare(n);
}
}
Step through the program with a debugger. Using n = 2 as an example, on your second loop through the for loop you get to this with i = 1 and j = 1:
if (magicSquare[i, j] != 0)
{
j -= 2;
i++;
continue;
}
And that makes i = 2 on the next loop through. Because there is no 2 index in the array you have created, it crashes when it gets to this same check the next loop.
Presumably odd numbers are working because they are getting floored on division (in the case of n = 5 -> i = 2).
That should be enough to point you in the right direction.
Related
given a binary number find the maximum consecutive 1s or 0s that can be obtained by flipping only one bit (either a 1 or a 0)
the code given was
public int getMacCon(string[] A)
{
int n = A.Length;
int result = 0;
for (int i = 0; i < n - 1; i++)
{
if (A[i] == A[i + 1])
result = result + 1;
}
int r = -2;
for (int i = 0; i < n; i++)
{
int count = 0;
if (i > 0)
{
if (A[i - 1] != A[i])
count = count + 1;
else
count = count - 1;
}
if (i < n - 1)
{
if (A[i + 1] != A[i])
count = count + 1;
else
count = count - 1;
}
r = Math.Max(r, count);
}
return result + r;
}
Im finding hard to figure out the logic here. specially the given below part
for (int i = 0; i < n - 1; i++)
{
if (A[i] == A[i + 1])
result = result + 1;
}
I would highly apretiate if any one can explain me the logic in this solution.
Thanks
The bit you've highlighted just counts the number of currently adjacent equal values, i.e. where one value (A[i]) is equal to the next (A[i+1]). It then asks (the second loop), for each value in turn, whether flipping it would increase vs decrease vs not change the number of adjacent equal values; so if a value is currently different from the one before it (A[i-1] != A[i]), a flip would be an increase - else decrease; likewise the one after it. The final result is the pre-existing number of adjacent equal values (result), plus the best delta (r) found in the sweep.
public int getMacCon(string[] A)
{
int n = A.Length;
int result = 0;
// find how many adjacent values are currently in the string
for (int i = 0; i < n - 1; i++)
{
// if same as the next value, that's a hit
if (A[i] == A[i + 1])
result = result + 1;
}
// worst case delta from flipping one value is that me make it
// worse on both sides, so -2
int r = -2;
// now consider each value in turn
for (int i = 0; i < n; i++)
{
int count = 0;
if (i > 0) // test value before, if not the first value
{
if (A[i - 1] != A[i])
count = count + 1; // before is different; flip is incr
else
count = count - 1; // before is same; flip is decr
}
if (i < n - 1) // test value after, if not the last value
{
if (A[i + 1] != A[i])
count = count + 1; // after is different; flip is incr
else
count = count - 1; // after is same; flip is decr
}
// compare that to the tracking counter, and keep the best value
r = Math.Max(r, count);
}
// final result is sum of pre-existing count plus the delta
return result + r;
}
Incidentally, an optimization might be to change the second loop test from i < n to i < n && r != 2 - i.e. stop as soon as the best possible delta is found (making it better on both sides, +2)
Not an direct answer to your question (as Marc Gravell's answer covers it enough) but I just need to add how would I solve this instead:
encode your string with RLE (run length encoding)
so you need array of b,v,n values. Where b>=0 is start position, v={0,1} is bit value and n is the count of consequent occurencies. For example something like:
const int _max=100; // max number of bits
int b[_max],v[_max],n[_max],bvns=0;
The bvns is number of used b,v,n in the arrays. You can also use any dynamic list/template instead.
reset your actual solution
You need bit position to change ix and the count of consequent bits resulting after its flip sz. Set booth to zero.
scan the RLE for items with n=1
if found that means item before and after in the RLE is the same so flipping will join them. So compute the resulting size and if bigger then store as actual solution something like:
for (int i=1;i<bvns-1;i++) // scann RLE except first and last item
if (n[i]==1) // single bit found
{
l=n[i-1]+1+n[i+1]; // resulting size
if (l>=sz) { sz=l; ix=b; } // update solution
}
test if enlarging single sequence is not bigger
simply:
for (int i=0;i<bvns;i++) // scann RLE
if (n[i]>=sz) // result is bigger?
{
sz=l; ix=b-1; // update solution
if (ix<0) ix=b+n[i];
}
I wrote this method for finding the longest increasing sub sequence in an array. My question is, after checking if the next index is higher in the second for loop, why do I have to even use the else block afterwards? It doesn't output a correct result if I don't. Why wouldn't it just be sufficient to increment currentSeq by 1 if the next one in the sequence is bigger? If false, than just move on with the flow of control, with currentSeq being left at 1 anyway?
static void Main(string[] args)
{
int length = int.Parse(Console.ReadLine());
int[] nums = new int[length];
int currentSeq = 1;
int maxSeq = 1;
for (int i = 0; i < nums.Length; i++)
{
nums[i] = int.Parse(Console.ReadLine());
}
for (int i = 0; i < nums.Length - 1; i++)
{
if (nums[i] < nums[i + 1])
{
currentSeq++;
}
else
{
currentSeq = 1;
}
if (currentSeq > maxSeq)
{
maxSeq = currentSeq;
}
}
Console.WriteLine(maxSeq);
}
You need the else keyword to reset currentSeq to 1 for the next sequence calculation. Imagine that you're done with the first sequence and you start calculating the next one in the table, you'll need to restart from 1.
Hey I am slightly new to C# it has been a week today. Ive managed to get this far but I cant seem to just out put the sum of the even numbers I've cubed i get the whole output and the last number is the total summed except i just want the last to show. Any help would be much appreciated and apologies for the horrendous code. Thanks
using System;
public class Test
{
public static void Main()
{
int j = 0; //Declaring + Assigning the interger j with 0
int Evennums = 0; // Declaring + Assigning the interger Evennums with 0
int Oddnums = 0; //Declaring + Assigning the interger Oddnums with 0
System.Console.WriteLine("Calculate the sum of all even numbers between 0 and the user’s number then cube it!"); //Telling console to write what is in ""
Console.WriteLine("Please enter a number");
uint i = uint.Parse(Console.ReadLine());
Console.WriteLine("You entered: " + i);
Console.WriteLine("Your number cubed: " + i*i*i);
if (i % 2 == 0)
while (j <= i * i * i)
{
if(j % 2 == 0)
{
Evennums += j; //or sum = sum + j;
Console.WriteLine("Even numbers summed together " + Evennums);
}
//increment j
j++;
}
else if(i%2 != 0)
//reset j to 0 like this: j=0;
j=0;
while (j<= i * i * i)
{
if (j%2 == 0)
{
Oddnums += j;
//Console.WriteLine(Oddnums);
}
//increment j
j++;
}
}
}
if you want to show the last sum, but not every summing process, change the location of print statement
if (i % 2 == 0)
{
while (j <= i * i * i)
{
if(j % 2 == 0)
{
Evennums += j; //or sum = sum + j;
}
//increment j
j++;
}
Console.WriteLine("Even numbers summed together " + Evennums);
}
same thing applies for the else if block.
You could try to achieve that you want like below, using LINQ:
// Calculate the cube of i.
int cube = i*i*i;
int sum = 0;
string message;
// Check if cube is even.
if(cube%2==0)
{
sum = Enumerable.Range(0,cube).Where(x => x%2==0).Sum();
message = "The sum of the even numbers in range [0,"+cube+"] is: ";
}
else // The cube is odd.
{
sum = Enumerable.Range(0,cube).Where(x => x%2==1).Sum();
message = "The sum of the odd numbers in range [0,"+cube+"] is: ";
}
// Print the sum.
Console.WriteLine(message+sum);
I am trying to achieve the following:
User enters 100 numbers and then the numbers are printed in 3 columns.
This is what I have so far, it works but it does not print the last value of the array.
What am I doing wrong?
static void Main(string[] args)
{
int digit = 0;
const int LIMIT = 100;
int[] row = new int[LIMIT];
for (int i = 0; i < row.Length; i++)
{
Console.WriteLine("Geef getal nummer " + (i + 1) + " in: ");
digit = int.Parse(Console.ReadLine());
row[i] = digit;
}
for (int i = 0; i < row.Length - 2; i+=3)
{
Console.WriteLine(row[i] + "\t" + row[i + 1] + "\t" + row[i + 2]);
}
}
Use this print instead
for (int i = 0; i < row.Length; i++)
{
Console.Write(row[i] + "\t");
if (i % 3 == 2)
Console.WriteLine();
}
Your issue is that you don't simply use Console.Write, and try to write your lines in one shot.
In fact, it would be even cleaner to use a StringBuilder here.
Replace
for (int i = 0; i < row.Length - 2; i+=3)
{
Console.WriteLine(row[i] + "\t" + row[i + 1] + "\t" + row[i + 2]);
}
by
StringBuilder sb = new StringBuilder();
int count = 0;
for (int i = 0; i < row.Length; i++)
{
count++;
if (count == 3)
{
sb.AppendLine(row[i])
count = 0;
}
else
sb.Append(row[i]).Append('\t');
}
Console.WriteLine(sb.ToString());
I think it's pretty explicit, but if you need clarifications, feel free to ask. Of course, the use of count here is pretty scholar, a real program could use % operator, like shown in other answers.
You have wrong condition in for loop. If you don't mind LINQ, you can use the following:
foreach (string s in row.Select((n, i) => new { n, i })
.GroupBy(p => p.i / 3)
.Select(g => string.Join("\t", g.Select(p => p.n))))
Console.WriteLine(s);
If you're not ok with LINQ, you can do this:
int colIndex = 0;
foreach (int n in row)
{
Console.Write(n);
if (colIndex == 2)
Console.WriteLine();
else
Console.Write('\t');
colIndex = (colIndex + 1) % 3;
}
jonavo is correct.
after 96+3 = 99
and you have done row.length-2, change it to row. length+2.
and in print dont print if the i+1 or I+2 >= max
It doesn't print it because 100 is not evenly divisible by 3 and your for-loop increases the variable by 3 on each iteration, so the last element wil be skipped.
Maybe this after the loop:
int rest = row.Length % 3;
if(rest > 0)
Console.WriteLine(row[row.Length - rest] + "\t" + row.ElementAtOrDefault(row.Length - rest + 1));
Its because of your index.
Your running index i goes from
0, 3, 6, 9, ... 96, 99
So this would output the array positions:
0,1,2 3,4,5 6,7,8 9,10,11 ... 96,97,98 99,100,101 (index out of bounds)
row.Length equals 100, so your loop-condition (i < row.Length - 2) is correct, but even better would be (i < row.Length - 3).
So your problem is how to print the last number... You see, you have 3 columns for 100 digits. This makes 33 rows and than there is one digit left.
Maybe you just add some Console.WriteLine(row[row.Length-1]); beneeth your loop.
Looks like you've got a lot of options at your disposal. Here's an approach using nested loops:
int numCols = 3;
for (int i = 0; i < row.Length; i += numCols)
{
for (int j = i; j < i + numCols && j < row.Length; j++)
{
Console.Write(row[j] + "\t");
}
Console.WriteLine();
}
Try this code.
Using this loop you can also change the number of rows/columns without code changes. Also, using the temporary buffer you output to the console an entire row at a time.
static void Main(string[] args)
{
int digit = 0;
const int LIMIT = 10;
const int COLS = 3;
int[] row = new int[LIMIT];
for (int i = 0; i < row.Length; i++)
{
Console.WriteLine("Geef getal nummer " + (i + 1) + " in: ");
// Re-try until user insert a valid integer.
while (!int.TryParse(Console.ReadLine(), out digit))
Console.WriteLine("Wrong format: please insert an integer number:");
row[i] = digit;
}
PrintArray(row, COLS);
// Wait to see console output.
Console.ReadKey();
}
/// <summary>
/// Print an array on console formatted in a number of columns.
/// </summary>
/// <param name="array">Input Array</param>
/// <param name="columns">Number of columns</param>
/// <returns>True on success, otherwise false.</returns>
static bool PrintArray(int[] array, int columns)
{
if (array == null || columns <= 0)
return false;
if (array.Length == 0)
return true;
// Build a buffer of columns elements.
string buffer = array[0].ToString();
for (int i = 1; i < array.Length; ++i)
{
if (i % columns == 0)
{
Console.WriteLine(buffer);
buffer = array[i].ToString();
}
else
buffer += "\t" + array[i].ToString();
}
// Print the remaining elements
if (array.Length % columns != 0)
Console.WriteLine(buffer);
return true;
}
Just for completeness
Note that int.Parse(Console.ReadLine()) can throw an Exception if unexpected characters are typed. It's better to use int.TryParse() as documented here. This method don't throw an exception but return a boolean that report a successful conversion.
while (!int.TryParse(Console.ReadLine(), out digit))
Console.WriteLine("Wrong format: please insert an integer number:");
This code tell the user that the typed string can't be interpreted as an integer and prompt again until a successful conversion is done.
here is the (not working code) and it should print the shape below but its not :
static void Main(string[] args)
{
int i = 1;
int k = 5;
int h = 1;
while (i <= 5)
{
Console.WriteLine("");
while (k > i)
{
Console.Write(" ");
k--;
}
while (h <= i)
{
Console.Write("**");
h++;
}
i++;
}
Console.ReadLine();
}
but when I try to do the same using the while statement the shape gets totally messed up.
any help ?
You have to declare k and h within the loop:
static void Main(string[] args)
{
int i = 1;
while (i <= 5)
{
int k = 5;
int h = 1;
Console.WriteLine("");
while (k > i)
{
Console.Write(" ");
k--;
}
while (h <= i)
{
Console.Write("**");
h++;
}
i++;
}
Console.ReadLine();
}
With your current solution, after first outer loop iteration, inner loops do nothing.
int NumberOfLines = 5;
int count = 1;
while (NumberOfLines-- != 0)
{
int c = count;
while (c-- != 0)
{
Console.Write("*");
}
Console.WriteLine();
count = count + 2;
}
That's it, simplest implementation.
The problem is that i, k and h are initialised before the outermost loop is entered. Within the outer loop k and h are altered by the inner loops. On the second execution of the outer loop k and h have the same values as were left after running the inner loops previously. As i increments in the outer loop, the k loop will not be entered and the h loop will only run once.
Think about what values h and k should have inside the outermost loop on the second execution.
I'll not solve for you just will give you hint only:
Use 3 loop statements
1. for line change
2. for spaces (reverse loop)
3. for printing * (odd series in this case) i.e. 2n-1
check in third while statement h <= 2*i - 1;
and print only one * in place of **
Check here:
http://ideone.com/xOB2OI
Actually I've done this via 'for' loop, z is height and x is equal to length of side.
Isosceles triangle (x>z):
public void Print(int x, int z)
{
var peakStart = x;
var peakEnd = x;
for (int i = 0; i < z; i++)
{
for (int j = 0; j < 2 * x + 1; j++)
{
if (peakStart < 1.5 * x && j >= peakStart && j <= peakEnd)
Console.Write("*");
else
Console.Write(" ");
}
peakStart--;
peakEnd++;
Console.WriteLine("");
}
}