fix search, add simple makefile and readme

README.txt

+interactive UI:
+$ make
+
+noninteractive test of each function:
+$ make test

llist.c

@@ -41,6 +41,7 @@ void print_list(NODE *head){
 }
 
 NODE_INT psearch(NODE *head, datatype data){
+//search for a value. prints updates
 //return:
 // positive : index where data was found; NODE* return is pointer to where
 // -1 : not found; NODE* return is NULL
@@ -54,9 +55,11 @@ NODE_INT psearch(NODE *head, datatype data){
 }
 
 NODE_INT search(NODE *head, datatype data){
+//searches for a value.
 //return:
-// positive : index where data was found; NODE* return is pointer to where
-// -1 : not found; NODE* return is NULL
+// NODE* is NULL : not found; int is index of last null
+// NODE* is non-null : int is index where data was found;
+//---------------------NODE* return is pointer to where
 	NODE_INT curr;
 	curr.node = head;
 	int i;
@@ -68,11 +71,13 @@ NODE_INT search(NODE *head, datatype data){
 		curr.node=curr.node->next;
 	}
 	curr.node = NULL;
-	curr.num = -1;
+	curr.num = i;
 	return curr;
 }
 
 NODE_INT search_before(NODE *head, datatype data, unsigned before){
+//searches for a value, then returns the item 'before' before it.
+//only traverses the list once.
 //return:
 // node non-null, num>=0 : normal; found data at index[num+before]
 // node NULL, num 0 : head is NULL
@@ -85,8 +90,9 @@ NODE_INT search_before(NODE *head, datatype data, unsigned before){
 	out.num = 0;
 	if(head==NULL)
 		return out;
-	if(before == 0)
+	if(before == 0){
 		return search(head,data);
+	}
 	before;
 	NODE **queue = calloc(before, sizeof(NODE*));
 	int i=0;
@@ -208,11 +214,11 @@ int delete_node(NODE *head, datatype data){
 // 0 : normal
 // 1 : head is NULL
 // 2 : data is sole item in list: this function will not free head
-// -1 : data not found
+// 4 : data not found
 	NODE_INT result = search_before(head,data,1);
 	if(result.node == NULL){
 		if(result.num > 0)//not found
-			return -1;
+			return 4;
 		if(result.num == 0)//head is null
 			return 1;
 		if(head->next == NULL)//data is sole item in list

makefile

+run : main.out
+	./main.out
+
+.PHONY : run all test
+
+test.out : llist.c llist.h test.c
+	gcc -o test.out llist.c test.c
+
+main.out : llist.c llist.h main.c
+	gcc -o main.out llist.c main.c
+
+all : test.out main.out
+
+test : test.out
+	./test.out

test.c

@@ -23,20 +23,28 @@ int main(){
 	printf("I found it at index %d.\n", target.num);
 	fputs("The number I found there was: ", stdout);
 	print_node(target.node);
-	puts("Deleting the element at index 3...");
 	target = traverse(root, 3);
+	fputs("At index 3 there is: ",stdout);
+	print_node(target.node);
+	puts("Deleting the element at index 3...");
 	delete_node_at(root, 3);
-	puts("Now it's garbage:");
+	fputs("Now it's garbage: ",stdout);
 	print_node(target.node);
-	puts("Deleting the first occurrence of 1...");
+	puts("Deleting the first occurrence of 5...");
 	target = search(root, 5);
 	delete_node(root, 5);
-	puts("Now it's garbage:");
+	fputs("Now it's garbage: ",stdout);
 	print_node(target.node);
 	print_list(root);
+	puts("Deleting the first item by index,");
+	delete_node_at(root, 0);
+	puts("and the new first item by value...");
+	delete_node(root, 3);
+	printf("The head is still at %p.\n",root);
+	print_list(root);
 	puts("Deleting list...");
 	delete_list(root);
-	puts("Now it's garbage:");
+	puts("Now it's garbage (or at least probably not data):");
 	print_list(root);
 
 	return 0;