main()
{
int index;
int matrix[20];

   for (index = 0;index < 20;index++)              /* generate data */
      matrix[index] = index + 1;

   for (index = 0;index < 5;index++)         /* print original data */
      printf("Start  matrix[%d] = %d\n",index,matrix[index]);

   dosome(matrix);              /* go to a function & modify matrix */

   for (index = 0;index < 5;index++)       /* print modified matrix */
      printf("Back   matrix[%d] = %d\n",index,matrix[index]);
} 

dosome(list)                 /* This will illustrate returning data */
int list[];
{
int i;

   for (i = 0;i < 5;i++)                   /* print original matrix */ 
      printf("Before matrix[%d] = %d\n",i,list[i]);

   for (i = 0;i < 20;i++)                   /* add 10 to all values */
      list[i] += 10;

   for (i = 0;i < 5;i++)                   /* print modified matrix */
      printf("After  matrix[%d] = %d\n",i,list[i]);
}