Answer to Question #180657 in C for jhon

Question

Write a program that will sort a list of strings (names of person) enter by the user given the value of n names.

Answer 1

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


struct list
{
    char name[20];
    struct list *next;
};


struct list * insert( struct list *node, char *name )
{
    struct list *tmp = malloc( sizeof( struct list ) );


    if ( tmp != NULL )
    {
        tmp->name = name;


        if ( node != NULL )
        {
            tmp->next = node->next;
            node->next = tmp;
        }
        else
        {
            tmp->next = NULL;
        }
    }


    return tmp;
}


void display( struct list *node )
{
    for ( ; node != NULL; node = node->next ) printf( "%s ", node->name );
}


struct list * clear( struct list *node )
{
    while ( node != NULL )
    {
        struct list *tmp = node;
        node = node->next;


        free( tmp );
    }


    return node;
}


struct list * sort( struct list *root )
{
    struct list *new_root = NULL;


    while ( root != NULL )
    {
        struct list *node = root;
        root = root->next;


        if ( new_root == NULL || node->name < new_root->name )
        {
            node->next = new_root;
            new_root = node;
        }
        else
        {
            struct list *current = new_root;
            while ( current->next != NULL && !( node->name < current->next->name ) )
            {
                  current = current->next;
            }


            node->next = current->next;
            current->next = node;
        }
    }


    return new_root;
}


#define N   4


int main()
{
    char names[N][20] = { "vasya", "petya", "kolya", "dima"};
    struct list *root = NULL;
    struct list **tmp = &root;


    for ( size_t i = 0; i < N; i++ )
    {
        *tmp = insert( *tmp, names[i] );
        tmp = &( *tmp )->next;
    }


    display( root );
    printf( "\n" );


    root = sort( root );


    display( root );
    printf( "\n" );


    root = clear( root );
}