0

I have created a linked list which stores data from file. However I got stuck when I try to print the contents of Linked List. The code is below

1.Text File

102.15.12.10
15.14.106.6
1591
1592
bit_torrent

102.15.12.10
15.14.106.6
1591
1592
bit_torrent

102.15.12.10
15.14.106.6
1591
1592
bit_torrent

102.15.12.10
15.14.106.6
1591
1592
bit_torrent

2.

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

	struct list_node{

		char src_ip[18];
		char dst_ip[18];
		char src_port[8];
		char dst_port[8];
		char protocol[18];

		struct list_node *next;

	};

	struct list_node showdata();
	struct list_node* buildlist(struct list_node anode,struct list_node *head);
	void print(struct list_node *firstnode);

int main()
{

	struct list_node *head;

	head=malloc(sizeof(struct list_node));

	print(buildlist(showdata(),head));
	print(buildlist(showdata(),head));

	return 0;
}

	 struct list_node showdata(){

		struct list_node anode;
		FILE *fp;

		if((fp = fopen("pkt_file.txt", "r"))==NULL) {
			printf("Cannot open file.\n");
			exit(1);
		}

	  fgets(anode.src_ip, 18, fp);
	  anode.src_ip[strlen(anode.src_ip)]='\0';
	 // printf("%s", anode.src_ip);

	  fgets(anode.dst_ip, 18, fp);
	  anode.dst_ip[strlen(anode.dst_ip)]='\0';
	  //printf("%s", anode.dst_ip);

	  fgets(anode.src_port, 8, fp);
	  anode.src_port[strlen(anode.src_port)]='\0';
	 // printf("%s", anode.src_port);

	  fgets(anode.dst_port, 8, fp);
	  anode.dst_port[strlen(anode.dst_port)]='\0';
	 // printf("%s", anode.dst_port);

	  fgets(anode.protocol, 18, fp);
	  anode.protocol[strlen(anode.protocol)]='\0';
	 // printf("%s\n", anode.protocol);


	  return (anode);

	  fclose(fp);

	}

	struct list_node* buildlist(struct list_node anode, struct list_node *head){

		struct list_node *current=NULL;
		current=malloc(sizeof(struct list_node));
		head=malloc(sizeof(struct list_node));

		current=head;

		if(current==NULL){

			head=current=&anode;
			printf("1--working\n");
			return head;
		}

		else if(current->next==NULL){

				current->next=&anode;
				head=current;
				printf("2--working\n");
				return head;
		}
		else{

			while(current->next!=NULL){

				current=current->next;
			}

			current->next=&anode;

			printf("working\n");
			return head;

		}





	}

	void print(struct list_node *firstnode){


			//firstnode=malloc(sizeof(struct list_node));

			if(firstnode->next==NULL){

			printf("The node is:%s\n",firstnode->dst_port);
			//firstnode=firstnode->next;
			}
			else{

				while(firstnode){

					printf("The node is:%s\n",firstnode->dst_port);
					firstnode=firstnode->next;
				}

			}

		}

Thanks in advance for help

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6 Years
Discussion Span
Last Post by JuhaW
0

At least there is bug at begin of buildlist:
head is argument of the fuction, but value of it is losed at begin of function. I cant't find any sense about malloc functions. First malloc just produces memory leak and second one just deletes argument.

#
struct list_node* buildlist(struct list_node anode, struct list_node *head){
#
 
#
struct list_node *current=NULL;
#
current=malloc(sizeof(struct list_node));
#
head=malloc(sizeof(struct list_node));
#
 
#
current=head;
#
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