exercise08.c

// C Primer Plus
// Chapter 12 Exercise 8:

// Here’s part of a program:

// [omitted]

// Complete the program by providing function definitions for make_array() and
// show_array(). The make_array() function takes two arguments. The first is
// the number of elements of an int array, and the second is a value that is to
// be assigned to each element. The function uses malloc() to create an array
// of a suitable size, sets each element to the indicated value, and returns a
// pointer to the array. The show_array() function displays the contents, eight
// numbers to a line.

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

int * make_array(int elem, int val);

void show_array(const int ar[], int n);

int main(void)
{
	int * pa;
	int size;
	int value;

	printf("Enter the number of elements: ");
	while (scanf("%d", &size) == 1 && size > 0)
	{
		printf("Enter the initialization value: ");
		scanf("%d", &value);

		pa = make_array(size, value);
		if (pa)
		{
			show_array(pa, size);
			free(pa);
		}
		printf("Enter the number of elements (<1 to quit): ");
	}
	printf("Done.\n");
	return 0;
}

int * make_array(int elem, int val)
{
	// generate and return pointer to a new array of ints
	// of length elem with each element initialized to val

	int *arr = (int *) malloc(elem * sizeof(int));

	if (arr != NULL)
		for (int i = 0; i < elem; i++)
			arr[i] = val;

	return arr;
}

void show_array(const int ar[], int n)
{
	// print contents of an array of ints, 8 elements to a line
	int i;
	for (i = 0; i < n; i++)
	{
		printf("%d ", ar[i]);
		if (i % 8 == 7)
			putchar('\n');
	}
	if (i % 8 != 0)
		putchar('\n');
}