1、

#include <stdio.h>

int main(void)
{
    int i, j, a[6][2], b[2] = {0}, c[6] = {0};
    puts("please input the elements of array a.");
    for(i = 0; i < 6; i++)
    {
        for(j = 0; j < 2; j++)
        {
            printf("a[%d][%d] = ", i, j); scanf("%d", &a[i][j]);
        }
    }
    puts("\nshow the matrix form of array a.");
    for(i = 0; i < 6; i++)
    {
        for(j = 0; j < 2; j++)
        {
            printf("%4d", a[i][j]);
        }
        putchar('\n');
    }
    putchar('\n');
    for(i = 0; i < 2; i++)
    {
        for(j = 0; j < 6; j++)
        {
            b[i] += a[j][i];
        }
        printf("sum majorNO.%d: %d, mean: %.2f\n", i + 1, b[i], (double)b[i] / 6);
    }
    
    putchar('\n');
    for(i = 0; i < 6; i++)
    {
        for(j = 0; j < 2; j++)
        {
            c[i] += a[i][j];
        }
        printf("sum student.NO.%d: %d, mean: %.2f\n", i + 1, c[i], (double)c[i] / 2);
    }
    
    return 0;
}