text_processing.c

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

struct node {
	char ch;
	struct node *next;
};

void append(struct node **head, char ch);
void insert(struct node **head, int pos, char ch);
void display_list(struct node *head);
int main(){
	int n;
	scanf("%d", &n);
	struct node *head = NULL;
	for(int i=0; i<n; i++)
	{
		char ch;
		scanf(" %c", &ch);
		append(&head, ch);
		
	}
	/* display_list(head); */
	int pos;
	char new_char;
	scanf("%d", &pos);
	scanf(" %c", &new_char);
	insert(&head, pos, new_char);
	printf("Updated list: ");
	display_list(head);
}

void append(struct node **head, char ch){
	struct node *new_node = (struct node *)malloc(sizeof(struct node));
	new_node->ch = ch;
	new_node->next = NULL;
	if(*head == NULL){
		*head=new_node;
		return;
	}
	struct node *tmp = *head;
	while(tmp->next != NULL){
		tmp = tmp->next;
	}
	tmp->next = new_node;
}
void insert(struct node **head, int pos, char ch){
	struct node *new_node=(struct node *)malloc(sizeof(struct node));
	new_node->ch = ch;
	new_node->next = NULL;
	struct node *tmp = *head;
	for(int i=0; i<pos && tmp!=NULL; i++)
		tmp = tmp->next;
	if (tmp==NULL){
		printf("Invalid index\n");
		return;
	}
	new_node->next = tmp->next;
	tmp->next = new_node;
}
void display_list(struct node *head){
	struct node *tmp = head;
	while(tmp != NULL)
	{
		printf("%c ", tmp->ch);
		tmp = tmp->next;
	}
}