How can I display only one list represented from the display function?-CodePudding

Basically I have 10 files named src(=source) and each of them has packets (named so for my homework) which are represented by roll number, dest(=destination) and gentime (=generation time). I want to have one list for each file, so 10 different lists, that will pass the packets in. But, when I display them, I have to have the option to display only one list, for example list 3, which will be for src file 3. My code is below.

void output( Node **head )
{
    for( Node *current =*head; current != NULL; current = current->next )
    {
        //printf( "%d %d %d %0.1f ",current->rollnumber, current->src, current->dst, current->gentime );
        printf("Roll Number:-\t",current->rollnumber);
        printf("src:-\t", current->src);
        printf("dest:-\t", current->dst);
        printf("gentime:%0.1f\n", current->gentime);
    }
    printf( "%s\n", "NULL" );
}

void display( Node **set, size_t n )
{
    for ( size_t i = 0; i <= n; i   )
    {
        output( set   );
        putchar( '\n' );
    }
}

The output is:

NULL

Roll Number: 8  src: 1  dest:10 gentime:89.1
Roll Number: 7  src: 1  dest:12 gentime:76.5
Roll Number: 6  src: 1  dest:10 gentime:64.1
Roll Number: 5  src: 1  dest: 4 gentime:51.5
Roll Number: 4  src: 1  dest:17 gentime:38.0
Roll Number: 3  src: 1  dest:20 gentime:25.9
Roll Number: 2  src: 1  dest:15 gentime:13.9
Roll Number: 1  src: 1  dest: 3 gentime:1.6
NULL

Roll Number: 8  src: 2  dest:12 gentime:90.6
Roll Number: 7  src: 2  dest: 6 gentime:78.1
Roll Number: 6  src: 2  dest:17 gentime:64.8
Roll Number: 5  src: 2  dest: 6 gentime:52.6
Roll Number: 4  src: 2  dest: 5 gentime:39.5
Roll Number: 3  src: 2  dest:20 gentime:26.0
Roll Number: 2  src: 2  dest:19 gentime:14.0
Roll Number: 1  src: 2  dest: 4 gentime:1.9
NULL

Roll Number: 8  src: 3  dest: 5 gentime:89.8
Roll Number: 7  src: 3  dest: 1 gentime:75.9
Roll Number: 6  src: 3  dest: 8 gentime:63.9
Roll Number: 5  src: 3  dest:14 gentime:50.8
Roll Number: 4  src: 3  dest:11 gentime:38.4
Roll Number: 3  src: 3  dest:16 gentime:25.7
Roll Number: 2  src: 3  dest:18 gentime:13.4
Roll Number: 1  src: 3  dest: 7 gentime:1.2
NULL

and so goes on until src:10

Also, the push function:

int push_front( Node **head, int rollnumber, int src, int dst, double gentime )
{
    Node *new_node = malloc( sizeof( Node ) );
    int success = new_node != NULL;

    if ( success )
    {
        new_node->rollnumber=rollnumber;
        new_node->src = src;
        new_node->dst=dst;
        new_node->gentime=gentime;
        new_node->next = *head;
        *head = new_node;
    }

    return success;
}

Code that calls display: (please don't mind the variables I have not mentioned, they have to do with another part of my code, just for checking).

for (i=1;i<=10;i  ){
            printf("intention[%d]=%d\n",i,intention[i]);
            if (intention[i]=true){
                printf("link[%d]:\n",i);
                display( link, sizeof( link ) / sizeof( *link ) );
            }
        }

How is it possible to display only one list whenever I call the function? Can anyone please tell me how to proceed?

Minimal Reproducible Example:

#include <stdio.h> 
#include <stdlib.h> 
#include <time.h>
#include <unistd.h>
#include <string.h>
#include <stdbool.h>
#define N   10

typedef struct Node 
{
    int rollnumber, src, dst;
    double gentime;
    struct Node *next;
} Node;

int push_front( Node **head, int rollnumber, int src, int dst, double gentime )
{
    Node *new_node = malloc( sizeof( Node ) );
    int success = new_node != NULL;

    if ( success )
    {
        new_node->rollnumber=rollnumber;
        new_node->src = src;
        new_node->dst=dst;
        new_node->gentime=gentime;
        new_node->next = *head;
        *head = new_node;
    }

    return success;
}
void output( Node **head )
{
    for( Node *current =*head; current != NULL; current = current->next )
    {
        printf( "%d %d %d %0.1f ",current->rollnumber, current->src, current->dst, current->gentime );
        
    }
    printf( "%s\n", "NULL" );
}

void display( Node **set, size_t n )
{
    for ( size_t i = 0; i <= n; i   )
    {
        output( set   );
        putchar( '\n' );
    }
}

int main(void) 
{
    int src,dst;
    int rollnumber;
    double gentime;
    Node * link[N] = { 0 };
    struct node * head = NULL;
     for(i=1;i<=10;i  ){
       //reading from a file : rollnumber, src, dst, gentime
       push_front( &link[i], rollnumber, src, dst, gentime );
       printf("link[%d]:\n",i);
                display( link, sizeof( link ) / sizeof( *link ) );
            }
}

CodePudding user response：

There are several problems:

for (int i = 1; i <= 10; i ) : array indexes start with 0, not with 1, so it should be for (int i = 0; i < 10; i )
There should not be a loop in display, you tell display which one of the lists in the array should be displayed, and that's all it should do.
Minor problem: output should get a Node* head, not a Node** head, because it only reads from the list, it does not modify the list.
Minor problem: don't use 10 but N.

Corrected code (as mcve with irrelevant code stripped and with fake test data):

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

#define N   10

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


int push_front(Node** head, int data)
{
  Node* new_node = malloc(sizeof(Node));
  int success = new_node != NULL;

  if (success)
  {
    new_node->data = data;
    new_node->next = *head;
    *head = new_node;
  }

  return success;
}

void output(Node* head)
{
  for (Node* current = head; current != NULL; current = current->next)
  {
    printf("%d ", current->data);
  }
}

void display(Node** set, int i)
{
    output(set[i]);
    putchar('\n');
}

int main(void)
{
  int testdata = 1;
  Node* link[N] = { 0 };
  struct node* head = NULL;

  for (int i = 0; i < N; i  ) {
    push_front(&link[i], testdata  );
    push_front(&link[i], testdata  );
  }

  for (int i = 0; i < N; i  ) {
    printf("link[%d]:", i);
    display(link, i);
  }
}