问c中的链接列表，意外结果

EN

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

typedef struct Tokens_read_in{
    char character;
    int number;
    char whichOne[5];
    struct Tokens_read_in* next;
}Tokens;

int main()
{

    //declare variables
    char c;

    //create a struct for the array that will hold the tokens
    Tokens* token_array;
    token_array = malloc(sizeof(Tokens));
    token_array->next = NULL;

    //open the input file
    FILE *ifp;  //input file pointer
    char *filename = "input.txt";
    ifp = fopen(filename, "r");

    if(!ifp){
        printf("Error in opening '%s' for reading!", filename);
        exit(0);
    }

    while(!feof(ifp)){

        //prepare to read in file one character at a time
        c = getc(ifp);

        //create a struct for the current token that is read in
        Tokens* current_token = token_array;

        //let the current_token point to the beginning of token_array
        current_token = token_array;

        //let the current_token point to the LAST of token_array
        while(current_token->next != NULL){
            current_token = current_token->next;
        }

        //create a node at the end of token_array
        current_token->next = malloc(sizeof(Tokens));

        //move the current_token to the last (new) of token_array
        current_token = current_token->next;
        if(current_token == NULL){
            printf("Out of memory");
            exit(0);
        }

        //plug character into current_token
        current_token->next = NULL;
        //letter
        if(isalpha(c)){
            printf("%c", c);
            current_token->character = c;
            strcpy(current_token->whichOne, "char");
        }
        //number
        else if(isdigit(c))
        {
            printf("%d", (int)c);
            current_token->number = (int)c;
            strcpy(current_token->whichOne, "num");
        }
        //space
        //this does not need to go into the token array
        else if (c == ' '){
            printf(" ");
        }
        //newline
        //this does not need to go into the token array
        else if (c == '\n'){
            printf("\n");
        }
        //anything else
        else if ((!isdigit(c) && !isalpha(c))){
            printf("%c", c);
            current_token->character = c;
            strcpy(current_token->whichOne, "char");
        }

        //now that the current_token is plugged into token_array, free current_token
        free(current_token);

    }//end while(!feof(ifp))

    //print the token_array
    Tokens* conductor;
    conductor = token_array;
    while(conductor != NULL){
        if(strcmp(conductor->whichOne, "num")){
            printf("%d ", conductor->number);
        }
        else if(strcmp(conductor->whichOne, "char")){
            printf("%c ", conductor->character);
        }
        conductor = conductor->next;
    }
    //done printing, so free conductor
    free(conductor);

    //done with program, so free token_array
    free(token_array);

    //close input file
    fclose(ifp);

    return 0;
}//end main

<I don't know why every beginner program says hello world,
but hello world anyway.>