ICT1.2: Labwork 6

do-not-read-me.md

After studying about pointers, labworks start to get interesting. So I decided to upload my solutions to compare with others. Hope some may find my implementations either helpful or amusing.

For exercise 4, please head to this commit. I felt that it was too long to be put together with 5-minute attempts.

Don't mind the file name tho, I put it that way so that the file will get alphabetically sorted before the labworks.

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

lab6-1.c

#include <stdio.h>

int main()
{
	int n, tmp, min, max; 

	/* No I don't like static arrays. */
	scanf("%d", &n);
	for (scanf("%d", &tmp), min = max = tmp; --n; scanf("%d", &tmp)) {
		if (tmp < min)
			min = tmp;
		if (tmp > max)
			max = tmp;
	}

	printf("%d %d\n", min, max);
	return 0;
}

lab6-2.c

#include <stdio.h>

int main()
{
	unsigned n;
	scanf("%u", &n);

	unsigned d = n / 2;
	unsigned even = d * (d + 1);
	printf("%u %u\n", even, n * (n + 1) / 2 - even);

	return 0;
}

lab6-3.c

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

void strswap(char *this, char *that, size_t n)
{
	while (n--) {
		this[n] ^= that[n];
		that[n] ^= this[n];
		this[n] ^= that[n];
	}
}

void bsort(void *base, size_t nmemb, size_t size,
           int (*compar)(const void *, const void *))
{
	char unsorted = 0;
	size_t length = (nmemb - 1) * size;
	do {
		unsorted = 0;
		for (size_t i = 0; i < length; i += size)
			if (compar(base + i, base + i + size) > 0) {
				strswap(base + i, base + i + size, size);
				unsorted = 1;
			}
	} while (unsorted);
}

void isort(void *base, size_t nmemb, size_t size,
           int (*compar)(const void *, const void *))
{
	size_t length = nmemb * size;
	for (size_t i = size; i < length; i += size)
		for (size_t j = i; j && compar(base + j, base + j - size) < 0;
		     j -= size)
			strswap(base + j, base + j - size, size);
}

void ssort(void *base, size_t nmemb, size_t size,
           int (*compar)(const void *, const void *))
{
	size_t length = nmemb * size;
	for (size_t i = 0; i < length - size; i += size)
		for (size_t j = i; j < length; j += size)
			if (compar(base + i, base + j) > 0)
				strswap(base + i, base + j, size);
}

int cmp(const void *x, const void *y)
{
	return *(int *) x - *(int *) y;
}

int main()
{
	size_t n;
	scanf("%zu", &n);

	int a[n];
	for (int i = 0; i < n; i++)
		scanf("%d", a + i);

	//bsort(a, n, sizeof(int), cmp);
	//isort(a, n, sizeof(int), cmp);
	//ssort(a, n, sizeof(int), cmp);
	qsort(a, n, sizeof(int), cmp);
	for (int i = 0; i < n; i++)
		printf("%d ", a[i]);
	putchar(10);

	return 0;
}

lab6-5.c

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

int main()
{
	size_t n;
	scanf("%zu ", &n);

	char *s = malloc(n + 1);
	fgets(s, n + 1, stdin);

	while (n--) putchar(s[n]);
	putchar(10);
}

lab6-6.c

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

int main()
{
	size_t n;
	scanf("%zu ", &n);

	char *s = malloc(n + 1);
	fgets(s, n + 1, stdin);

	size_t i, count = 0;
	for (i = 0; i < n; i++)
		if (s[i] == 97)
			count++;

	printf("%zu\n", count);
	for (i = 0; i < n; i++)
		if (s[i] == 97)
			printf("%zu ", i);
	putchar(10);

	return 0;
}

lab6-7.c

#include <stdio.h>

int main()
{
	size_t n;
	char x, c;
	scanf("%zu %c", &n, &x);

	while (n--)
		if ((c = getchar()) != x)
			putchar(c);
	putchar(10);

	return 0;
}

labwork6.pdf