mirror of
https://github.com/mfocko/blog.git
synced 2024-09-20 10:26:55 +02:00
264 lines
7.2 KiB
C
264 lines
7.2 KiB
C
#include <assert.h>
|
|
#include <stdbool.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
/* If you want to see arrays before and after sorting, uncomment next line */
|
|
// #define DEBUG_OUTPUT
|
|
|
|
/**
|
|
* @brief Swaps two elements at given addresses of given size.
|
|
* @param left Pointer to the first element.
|
|
* @param right Pointer to the second element.
|
|
* @param size Size of the memory one element takes.
|
|
*/
|
|
void swap(void *left, void *right, size_t size)
|
|
{
|
|
/* TODO */
|
|
}
|
|
|
|
/**
|
|
* @brief Get index of biggest element in the array.
|
|
* @param ptr Pointer to the first element of the array.
|
|
* @param count Count of the elements in the array.
|
|
* @param size Size of one element in the array.
|
|
* @param comp Comparator that is used to decide ordering of the elements.
|
|
* @returns Index of the biggest element given the ordering.
|
|
*/
|
|
size_t maximum(void *ptr, size_t count, size_t size, int (*comp)(const void *, const void *))
|
|
{
|
|
/* Pseudocode:
|
|
* ===========
|
|
* max_index <- 0
|
|
* FOR i <- 1 TO n - 1 DO
|
|
* IF A[i] > A[max_index] THEN
|
|
* max_index <- i
|
|
* FI
|
|
* OD
|
|
* RETURN max_index
|
|
*/
|
|
/* TODO */
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* @brief Sort array in-situ using select-sort.
|
|
* @param ptr Pointer to the first element of the array.
|
|
* @param count Count of the elements in the array.
|
|
* @param size Size of one element in the array.
|
|
* @param comp Comparator that is used to decide ordering of the elements.
|
|
*/
|
|
void select_sort(void *ptr, size_t count, size_t size, int (*comp)(const void *, const void *))
|
|
{
|
|
/* Pseudocode:
|
|
* ===========
|
|
* FOR i <- n - 1 DOWNTO 1 DO
|
|
* j <- MAXIMUM(A, i + 1)
|
|
* SWAP(A, i, j)
|
|
* OD
|
|
*/
|
|
/* TODO */
|
|
}
|
|
|
|
/**
|
|
* @brief Compares two integers that are given through generic pointers.
|
|
* @param x Pointer to the integer x.
|
|
* @param y Pointer to the integer y.
|
|
* @returns 0 if x == y, <0 if x < y, >0 otherwise.
|
|
*/
|
|
static int int_comparator(const void *x, const void *y)
|
|
{
|
|
/* TODO */
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* @brief Compares two characters by ASCII value.
|
|
* @param x Pointer to the character x.
|
|
* @param y Pointer to the character y.
|
|
* @returns 0 if x == y, <0 if x < y, >0 otherwise.
|
|
*/
|
|
static int char_comparator(const void *x, const void *y)
|
|
{
|
|
char x_value = *(const char *) x;
|
|
char y_value = *(const char *) y;
|
|
return x_value - y_value;
|
|
}
|
|
|
|
/**
|
|
* @brief Compares two characters by ASCII value in a reversed order.
|
|
* @param x Pointer to the character x.
|
|
* @param y Pointer to the character y.
|
|
* @returns 0 if x == y, >0 if x < y, <0 otherwise.
|
|
*/
|
|
static int char_reversed_comparator(const void *x, const void *y)
|
|
{
|
|
char x_value = *(const char *) x;
|
|
char y_value = *(const char *) y;
|
|
return y_value - x_value;
|
|
}
|
|
|
|
// #pragma region TESTS
|
|
/**
|
|
* @brief Check if array is sorted.
|
|
* @param ptr Pointer to the first element of the array.
|
|
* @param count Count of the elements in the array.
|
|
* @param size Size of one element in the array.
|
|
* @param comp Comparator that is used to decide ordering of the elements.
|
|
*/
|
|
static void check_if_sorted(void *ptr, size_t count, size_t size, int (*comp)(const void *, const void *))
|
|
{
|
|
char *left = ptr;
|
|
char *right = (char *) ptr + size;
|
|
|
|
for (size_t i = 0; i < count - 1; i++) {
|
|
assert(comp(left, right) <= 0);
|
|
|
|
left += size;
|
|
right += size;
|
|
}
|
|
}
|
|
|
|
#ifdef DEBUG_OUTPUT
|
|
/**
|
|
* @brief Print numbers from an array.
|
|
* @param array Pointer to the first element of the array.
|
|
* @param count Count of the elements in the array.
|
|
*/
|
|
static void print_numbers(int *array, size_t count)
|
|
{
|
|
for (size_t i = 0; i < count; i++) {
|
|
printf(" %d", array[i]);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* @brief Run some basic tests on integer arrays.
|
|
*/
|
|
static void check_int_arrays()
|
|
{
|
|
/* You are free to add any other examples you like, in case you want to add
|
|
* array with more than 10 elements, please adjust the size.
|
|
*/
|
|
|
|
size_t examples_count = 5;
|
|
int examples[][10] = {
|
|
{ -1, 50, -10, 20, 30, 0, -100 },
|
|
{ -100, 0, 30, 20, -10, 50, -1 },
|
|
{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 },
|
|
{ -1, -2, -3, -4, -5, -6, -7, -8, -9, -10 },
|
|
{ 0, 0, 0, 0, 0, 0, 0, 0 }
|
|
};
|
|
|
|
printf("[TEST] Integer arrays\n");
|
|
for (size_t i = 0; i < examples_count; i++) {
|
|
size_t count = sizeof(examples[i]) / sizeof(int);
|
|
|
|
#ifdef DEBUG_OUTPUT
|
|
printf("Before sorting:");
|
|
print_numbers(examples[i], count);
|
|
putchar('\n');
|
|
#endif
|
|
|
|
select_sort(examples[i], count, sizeof(int), int_comparator);
|
|
|
|
#ifdef DEBUG_OUTPUT
|
|
printf("After sorting:");
|
|
print_numbers(examples[i], count);
|
|
printf("\n\n");
|
|
#endif
|
|
|
|
check_if_sorted(examples[i], count, sizeof(int), int_comparator);
|
|
}
|
|
printf("[PASS] Tests passed.\n\n");
|
|
}
|
|
|
|
/**
|
|
* @brief Run some basic tests on strings. Also with reversed ordering.
|
|
*/
|
|
static void check_char_arrays()
|
|
{
|
|
#define MAX_SIZE 20
|
|
/* You are free to add any other examples you like, in case you want to add
|
|
* strings with more than 10 characters, please adjust the size.
|
|
* mind the terminator ;)
|
|
*/
|
|
|
|
const size_t examples_count = 5;
|
|
char examples[][MAX_SIZE] = {
|
|
"Hello World!",
|
|
"hi",
|
|
"aloha",
|
|
"LET US SORT",
|
|
"LeT uS sOrT"
|
|
};
|
|
|
|
printf("[TEST] Char arrays\n");
|
|
for (size_t i = 0; i < examples_count; i++) {
|
|
size_t count = strlen(examples[i]);
|
|
|
|
char temp_array[MAX_SIZE];
|
|
strncpy(temp_array, examples[i], MAX_SIZE);
|
|
select_sort(temp_array, count, 1, char_comparator);
|
|
|
|
#ifdef DEBUG_OUTPUT
|
|
printf("Before sorting: \"%s\"\n", examples[i]);
|
|
printf("After sorting: \"%s\"\n\n", temp_array);
|
|
#endif
|
|
|
|
check_if_sorted(temp_array, count, 1, char_comparator);
|
|
}
|
|
printf("[PASS] Tests passed.\n\n");
|
|
|
|
printf("[TEST] Char arrays reversed\n");
|
|
for (size_t i = 0; i < examples_count; i++) {
|
|
size_t count = strlen(examples[i]);
|
|
|
|
char temp_array[MAX_SIZE];
|
|
strncpy(temp_array, examples[i], MAX_SIZE);
|
|
select_sort(temp_array, count, 1, char_reversed_comparator);
|
|
|
|
#ifdef DEBUG_OUTPUT
|
|
printf("Before sorting: \"%s\"\n", examples[i]);
|
|
printf("After sorting: \"%s\"\n\n", temp_array);
|
|
#endif
|
|
|
|
check_if_sorted(temp_array, count, 1, char_reversed_comparator);
|
|
}
|
|
printf("[PASS] Tests passed.\n\n");
|
|
#undef MAX_SIZE
|
|
}
|
|
|
|
static void annotate(const char *description, bool result)
|
|
{
|
|
printf("[TEST] %s\n", description);
|
|
assert(result);
|
|
printf("[PASS] Test passed.\n\n");
|
|
}
|
|
|
|
static void check_int_comparator()
|
|
{
|
|
int a = 5, b = -10, c = -10;
|
|
|
|
annotate("Test comparator for: a > b", int_comparator(&a, &b) > 0);
|
|
annotate("Test comparator for: b < a", int_comparator(&b, &a) < 0);
|
|
annotate("Test comparator for: b = c", int_comparator(&b, &c) == 0);
|
|
annotate("Test comparator for: a = a", int_comparator(&a, &a) == 0);
|
|
annotate("Test comparator for: b = b", int_comparator(&b, &b) == 0);
|
|
annotate("Test comparator for: c = c", int_comparator(&c, &c) == 0);
|
|
}
|
|
// #pragma endregion TESTS
|
|
|
|
int main(void)
|
|
{
|
|
/* Neither of those tests check for bad behaviour, like overwriting array
|
|
* with elements satisfying ordering. **I** check those :scheming:
|
|
*/
|
|
check_int_comparator();
|
|
check_int_arrays();
|
|
check_char_arrays();
|
|
|
|
return 0;
|
|
}
|