array-09.c

#include <stdio.h>
#include <stdlib.h>

void main(void)
{
    int Upper[5][5] = { 3, 9, 1, 4, 7,
                        0, 5, 2, 5, 8,
                        0, 0, 5, 2, 4,
                        0, 0, 0, 1, 7,
                        0, 0, 0, 0, 9 };
    int ColMajor[15];
    int Index;
    int i, j;

    printf("Two dimensional upper triangle array;\n");

    for(i = 0; i < 5; i++)
    {
        for(j = 0; j < 5; j++)
            printf("%3d", Upper[i][j]);
        printf("\n");
    }

    for(i = 0; i < 5; i++)
        for(j = 0; j < 5; j++)
        if(i <= j)
        {
            Index = j * (j + 1) / 2 + i;
            ColMajor[Index] = Upper[i][j];
        }
    printf("\n");

    printf("Column Major one dimensional array:\n");
    for(i = 0; i < 15; i++)
        printf("%3d", ColMajor[i]);
    printf("\n");
}