Arrays

Using arrays, the C# code would be:

using System;

class Pascal

{

static void Main()

{

Console.Write("Input number of rows to generate (1 to 17) : ");

int n;

int.TryParse(Console.ReadLine(), out n);

if (n < 1)

{

Console.WriteLine("Can't be less than one!");

return;

}

else if (n > 17)

{

Console.WriteLine("Too big to display on console!");

return;

}

int[][] rows = new int[n][];

for(int i = 0; i < n; i++)

{

rows[i] = new int[i + 1];

rows[i][0] = 1;

if (i > 0) rows[i][i] = 1;

if (i > 1)

{

for(int j = 1; j < i; j++)

{

rows[i][j] = rows[i-1][j-1] + rows[i-1][j];

}

Console.Clear();

int totalLen = n - 1;

for(int i = 0; i < n; i++) totalLen += rows[n-1][i].ToString().Length;

for(int i = 0; i < n; i++)

{

int currLen = i;

for(int j = 0; j < i + 1; j++) currLen += rows[i][j].ToString().Length;

int offset = (totalLen - currLen) / 2;

Console.Write(new string(' ', offset));

for(int j = 0; j < i + 1; j++) Console.Write("{0} ", rows[i][j]);

Console.WriteLine();

}

Console.ReadKey();

}

}

Without using arrays (i.e. using the binomial coefficients instead), the code would be:

using System;

class Pascal2

{

static void Main()

{

Console.Write("Input number of rows to generate (1 to 17) : ");

int n;

int.TryParse(Console.ReadLine(), out n);

if (n < 1)

{

Console.WriteLine("Can't be less than one!");

return;

}

else if (n > 17)

{

Console.WriteLine("Too big to display on console!");

return;

}

Console.Clear();

for(int i = 0; i < n; i++)

{

for(int j = 0; j < i + 1; j++)

{

int k = i - j;

long coeff = Factorial(i)/Factorial(j)/Factorial(k);

Console.Write("{0} ", coeff);

}

Console.WriteLine();

}

Console.ReadKey();

}

static long Factorial(int n)

{

if (n <= 1) return 1;

return n * Factorial(n - 1);

}

}

In this second case, you can only really display the numbers as a right-angled rather than an equilateral triangle as you don't know how long each line will be until you've generated the numbers.

1 Reply

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Vulpes15y ago
Using arrays, the C# code would be:

using System;

class Pascal
{
static void Main()
{
Console.Write("Input number of rows to generate (1 to 17) : ");
int n;
int.TryParse(Console.ReadLine(), out n);

if (n < 1)
{
Console.WriteLine("Can't be less than one!");
return;
}
else if (n > 17)
{
Console.WriteLine("Too big to display on console!");
return;
}

int[][] rows = new int[n][];

for(int i = 0; i < n; i++)
{
rows[i] = new int[i + 1];
rows[i][0] = 1;
if (i > 0) rows[i][i] = 1;

if (i > 1)
{
for(int j = 1; j < i; j++)
{
rows[i][j] = rows[i-1][j-1] + rows[i-1][j];
}
}
}

Console.Clear();

int totalLen = n - 1;

for(int i = 0; i < n; i++) totalLen += rows[n-1][i].ToString().Length;

for(int i = 0; i < n; i++)
{
int currLen = i;
for(int j = 0; j < i + 1; j++) currLen += rows[i][j].ToString().Length;
int offset = (totalLen - currLen) / 2;
Console.Write(new string(' ', offset));
for(int j = 0; j < i + 1; j++) Console.Write("{0} ", rows[i][j]);
Console.WriteLine();
}

Console.ReadKey();
}
}

Without using arrays (i.e. using the binomial coefficients instead), the code would be:

using System;

class Pascal2
{
static void Main()
{
Console.Write("Input number of rows to generate (1 to 17) : ");
int n;
int.TryParse(Console.ReadLine(), out n);

if (n < 1)
{
Console.WriteLine("Can't be less than one!");
return;
}
else if (n > 17)
{
Console.WriteLine("Too big to display on console!");
return;
}

Console.Clear();

for(int i = 0; i < n; i++)
{
for(int j = 0; j < i + 1; j++)
{
int k = i - j;
long coeff = Factorial(i)/Factorial(j)/Factorial(k);
Console.Write("{0} ", coeff);
}

Console.WriteLine();
}

Console.ReadKey();
}

static long Factorial(int n)
{
if (n <= 1) return 1;
return n * Factorial(n - 1);
}
}

In this second case, you can only really display the numbers as a right-angled rather than an equilateral triangle as you don't know how long each line will be until you've generated the numbers.