/*
 * Program to demonstrate using array(s).
 *
 * Defines and prints an array of "random" values and then prompts
 * user to specify an index to change.  
 * Notice that specifying an index out of range is wrong but may or may
 * not cause immediate trouble.  That's C.
 */
#include <stdio.h>
#include <stdlib.h>

/* FIXME?  arguably these should both be obtained from the user */
#define ASIZE 10
#define SEED 5

void printarray(int size, int nums[]) {
	printf("size of array in printarray %d\n", (int) sizeof(nums));
	for (int i = 0; i < size; ++i) {
		printf("nums[%d] is %d\n", i, nums[i]);
	}
}
/* alternate version using C99 syntax for VLA argument 
void printarray(int size, int nums[size]) {
	printf("size of array in printarray %d\n", (int) sizeof(nums));
	for (int i = 0; i < size; ++i) {
		printf("nums[%d] is %d\n", i, nums[i]);
	}
}
*/

void fillwithrandom(int size, int nums[]) {
	srand(SEED);
	for (int i = 0; i < size; ++i) {
		nums[i] = rand();
	}
}

int main(void) {

	int nums[ASIZE];
	printf("size of array in main %d\n", (int) sizeof(nums));
	fillwithrandom(ASIZE, nums);
	printarray(ASIZE, nums);
	printf("enter index\n");
	int index;
	if (scanf("%d", &index) != 1) {
		printf("invalid\n");
		return 1; /* bail out */
	}
	if ((index < 0) || (index >= ASIZE)) {
		printf("out of bounds -- good luck\n");
	}
	nums[index] = 100;
	printarray(ASIZE, nums);

	return 0;
}