OAIP/19-20/20.c

#include <stdio.h>
#include <Windows.h>

void printList(), clearList(), addToHead(int);
int deleteFromHead(), contains(int);

void oddX10(), iX100(int), lessiX10(int);


typedef struct NODE {
	int data;
	struct NODE* next;
} Node;

Node* arr = NULL;

int main() {
	arr = NULL;
	printList();

	addToHead(1);
	printList();

	addToHead(2);
	printList();

	addToHead(3);
	printList();

	addToHead(4);
	addToHead(5);
	printList();

	printf("DELETE\n");
	deleteFromHead();
	printList();

	int ans = 0;

	scanf_s("%d", &ans);
	printf("contains %d %d\n\n", ans, contains(ans));

	printf("summ = %d\n\n", sum());

	printf("k%%2==0 = %d\n\n", evenCount());

	printf("ODD X 10\n");
	oddX10();
	printList();

	scanf_s("%d", &ans);
	printf("a[%d] X 100\n", ans);
	iX100(ans);
	printList();

	scanf_s("%d", &ans);
	printf("less a[%d] X 10\n", ans);
	lessiX10(ans);
	printList();

	clearList();
	printList();
}

void printList() {
	Node* ptr = arr;
	while (ptr != NULL) {
		printf("(%d) -> ", ptr->data);
		ptr = ptr->next;
	}
	printf("NULL\n\n");
}

void addToHead(int value) {
	Node* newNode = (struct Node*)malloc(sizeof(Node));

	newNode->next = arr;
	newNode->data = value;

	arr = newNode;
}

int deleteFromHead() {
	int value = arr->data;
	 Node* delNode = arr;
	arr = arr->next;
	free(delNode);
	return value;
}

int contains(int value) {
	Node* ptr = arr;
	while (ptr != NULL) {
		if (ptr->data == value) {
			return 1;
		}
		ptr = ptr->next;
	}
	return 0;
}

void clearList() {
	while (arr != NULL)
	{
		Node* delNode = arr;
		arr = arr->next;
		free(delNode);
	}
}

int sum() {
	Node* ptr = arr;
	int s = 0;
	while (ptr != NULL) {
		s += ptr->data;
		ptr = ptr->next;
	}
	return s;
}

int evenCount() {
	Node* ptr = arr;
	int k = 0;
	while (ptr != NULL) {
		if (ptr->data % 2 == 0) {
			k++;
		}
		ptr = ptr->next;
	}
	return k;
}

void oddX10() {
	Node* ptr = arr;
	while (ptr != NULL) {
		if (ptr->data % 2 != 0) {
			ptr->data *= 10;
		}
		ptr = ptr->next;
	}
}

void iX100(int i) {
	Node* ptr = arr;
	int index = 0;
	while (ptr != NULL) {
		if (index == i) {
			ptr->data *= 100;
			return;
		}
		index += 1;
		ptr = ptr->next;
	}
}

void lessiX10(int i) {
	Node* ptr = arr;
	int index = 0;
	while (ptr != NULL) {
		if (index < i) {
			ptr->data = ptr->data * 10;
		}
		if (index == i) {
			return;
		}
		index += 1;
		ptr = ptr->next;
	}
}