Practice Linked Lists

//Written by Michael Simarta
//With the help of Bernice Chen
//List2.c file that implements all functions declared in List2.h
//implement the removeUpperCase() functions here

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "list2.h"

typedef struct _node {
    char value;
    Node next;
} node;

typedef struct _list {
    Node head;
} list;

//when the removeUpperCase() function is complete,
//compile with testList2.c, type
//"gcc -Wall -Werror -O -o test testList2.c List2.c"
//to run program, type
//"./test"

//TODO
//Read List2.h to help you look at the hints
//remove values which are uppercase
//
//given a list X
//(Empty List)
//then removeUpperCase(list);
//the list is still X
//
//given a list a->X
//then removeUpperCase(list);
//the list is a->X
//
//given a list A->X
//then removeUpperCase(list);
//the list is X
//
//given a list A->a->X
//then removeUpperCase(list);
//the list is a->X
//
//given a list C->a->A->D->X
//then removeUpperCase(list);
//the list is a->X
//
//given a list A->a->B->b->C->c->d->D->E->e->X
//then removeUpperCase(list);
//the list is a->b->c->d->e->X

void removeUpperCase(List l) {

    Node current = l->head;

    // when l is empty
    if (current->next == NULL) {
        current = NULL;

    } else {
        while (current->next != NULL) {
            if((current->value <= 'a')) {
                Node savePtr = current->next;
                free(current);
                current = savePtr;
            }

        }
    }

}

//returns a new list of length 0
List newList() {
    List l = malloc(sizeof(list));
    assert ( l!=NULL );
    l->head = NULL;
    return l;
}

//frees everything malloced for the list
void destroy(List l) {
    Node curNode = l->head;
    Node prevNode = NULL;

    while (curNode != NULL) {
        prevNode = curNode;
        curNode = prevNode->next;
        free(prevNode);
    }

    free(l);
}

//appends a node of value to the end of the list
void append(List l, char value) {
    Node newNode = malloc(sizeof(node));
    newNode->value = value;
    newNode->next = NULL;
    Node curNode = l->head;
    if ( curNode==NULL ) {
        l->head = newNode;
    } else {
        while ( curNode->next!=NULL ) {
            curNode = curNode->next;
        }
        curNode->next = newNode;
    }
}

//returns the int value of the node at index
//assumes input index is within range of the list's length
char getValue(List l, int index) {

    Node curNode = l->head;
    assert (curNode!=NULL);
    int counter = 0;
    while (counter<index) {
        curNode = curNode->next;
        counter++;
    }
    return curNode->value;
}