Task: Pascal matrix generation
C: #include <stdio.h>
#include <stdlib.h>

void pascal_low(int **mat, int n) {
    int i, j;

    for (i = 0; i < n; ++i)
        for (j = 0; j < n; ++j)
            if (i < j)
                mat[i][j] = 0;
            else if (i == j || j == 0)
                mat[i][j] = 1;
            else
                mat[i][j] = mat[i - 1][j - 1] + mat[i - 1][j];
}

void pascal_upp(int **mat, int n) {
    int i, j;

    for (i = 0; i < n; ++i)
        for (j = 0; j < n; ++j)
            if (i > j)
                mat[i][j] = 0;
            else if (i == j || i == 0)
                mat[i][j] = 1;
            else
                mat[i][j] = mat[i - 1][j - 1] + mat[i][j - 1];
}

void pascal_sym(int **mat, int n) {
    int i, j;

    for (i = 0; i < n; ++i)
        for (j = 0; j < n; ++j)
            if (i == 0 || j == 0)
                mat[i][j] = 1;
            else
                mat[i][j] = mat[i - 1][j] + mat[i][j - 1];
}

int main(int argc, char * argv[]) {
    int **mat;
    int i, j, n;

    
    n = 5;

    
    mat = calloc(n, sizeof(int *));
    for (i = 0; i < n; ++i)
        mat[i] = calloc(n, sizeof(int));

    
    printf("=== Pascal upper matrix ===\n");
    pascal_upp(mat, n);
    for (i = 0; i < n; i++)
        for (j = 0; j < n; j++)
            printf("%4d%c", mat[i][j], j < n - 1 ? ' ' : '\n');

    printf("=== Pascal lower matrix ===\n");
    pascal_low(mat, n);
    for (i = 0; i < n; i++)
        for (j = 0; j < n; j++)
            printf("%4d%c", mat[i][j], j < n - 1 ? ' ' : '\n');

    printf("=== Pascal symmetric matrix ===\n");
    pascal_sym(mat, n);
    for (i = 0; i < n; i++)
        for (j = 0; j < n; j++)
            printf("%4d%c", mat[i][j], j < n - 1 ? ' ' : '\n');

    return 0;
}

C#: using System;

public static class PascalMatrixGeneration
{
    public static void Main() {
        Print(GenerateUpper(5));
        Console.WriteLine();
        Print(GenerateLower(5));
        Console.WriteLine();
        Print(GenerateSymmetric(5));
    }

    static int[,] GenerateUpper(int size) {
        int[,] m = new int[size, size];
        for (int c = 0; c < size; c++) m[0, c] = 1;
        for (int r = 1; r < size; r++) {
            for (int c = r; c < size; c++) {
                m[r, c] = m[r-1, c-1] + m[r, c-1];
            }
        }
        return m;
    }

    static int[,] GenerateLower(int size) {
        int[,] m = new int[size, size];
        for (int r = 0; r < size; r++) m[r, 0] = 1;
        for (int c = 1; c < size; c++) {
            for (int r = c; r < size; r++) {
                m[r, c] = m[r-1, c-1] + m[r-1, c];
            }
        }
        return m;
    }

    static int[,] GenerateSymmetric(int size) {
        int[,] m = new int[size, size];
        for (int i = 0; i < size; i++) m[0, i] = m[i, 0] = 1;
        for (int r = 1; r < size; r++) {
            for (int c = 1; c < size; c++) {
                m[r, c] = m[r-1, c] + m[r, c-1];
            }
        }
        return m;
    }

    static void Print(int[,] matrix) {
        string[,] m = ToString(matrix);
        int width = m.Cast<string>().Select(s => s.Length).Max();
        int rows = matrix.GetLength(0), columns = matrix.GetLength(1);
        for (int row = 0; row < rows; row++) {
            Console.WriteLine("|" + string.Join(" ", Range(0, columns).Select(column => m[row, column].PadLeft(width, ' '))) + "|");
        }
    }

    static string[,] ToString(int[,] matrix) {
        int rows = matrix.GetLength(0), columns = matrix.GetLength(1);
        string[,] m = new string[rows, columns];
        for (int r = 0; r < rows; r++) {
            for (int c = 0; c < columns; c++) {
                m[r, c] = matrix[r, c].ToString();
            }
        }
        return m;
    }
    
}