exercise05.c

// C Primer Plus
// Chapter 12 Exercise 5:

// Write a program that generates a list of 100 random numbers in the range
// 1–10 in sorted decreasing order. (You can adapt the sorting algorithm from
// Chapter 11, “Character Strings and String Functions,” to type int. In this
// case, just sort the numbers themselves.)

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

void random_ints(int *int_array);

int main(void)
{
	// test random ints
	int int_array[100];
	random_ints(int_array);

	for (int i = 0; i < 100; i++)
	{
		printf("%2d ", int_array[i]);
		if (i % 20 == 19)
			putchar('\n');
	}

	putchar('\n');
	return 0;
}

void random_ints(int *int_array)
{
	int tmp;

	// initialize array
	for (int i = 0; i < 100; i++)
		int_array[i] = rand() % 10 + 1;
	
	// sort array in decreasing order
	for (int i = 0; i < 99; i++)
		for (int j = i + 1; j < 100; j++)
		{
			if (int_array[i] < int_array[j])
			{
				tmp = int_array[i];
				int_array[i] = int_array[j];
				int_array[j] = tmp;
			}
		}
}