您好,我是 C 的新程序员,我的链表程序中出现段错误,我想知道是否有人可以帮助我。我已经在下面发布了我的代码...如果您需要更多信息,我会发布它。谢谢。
#include "list.h"
//+-------------------------------------------------------------
//+ CREATE NODE
//+
//+ Allocate memory for a node of type struct node and
//+ initialize it with d. Return a pointer to the new node.
//+-------------------------------------------------------------
struct node* createNode(int d){
struct node* newNode = malloc(sizeof(struct node)); //create and allocate space in memory for a new node called newNode
newNode->item = d; //newNode's data is the value stored in 'd'
newNode->next = NULL; //sets the pointer to the next node to NULL
return newNode; //return the new node created
}
//+-------------------------------------------------------------
//+ INSERT HEAD NODE
//+
//+ Insert Node n in front of the head of the list, and set
//+ n to be the new head of the list.
//+-------------------------------------------------------------
void insertHead(struct node **headRef, struct node *n){
struct node* newNode = malloc(sizeof(struct node)); //create and allocate space in memory for a new node called newNode
newNode->item = n->item; //newNode's data is assigned the value of the parameter node n''
newNode->next = *headRef; //since we are inserting the node at the head we set the next node to be the head reference
*headRef = newNode; //and then we assign the head reference to the new node created, thus, inserting the head node
}
//+-------------------------------------------------------------
//+ INSERT TAIL NODE
//+
//+ Insert Node n at the tail of the LinkedList.
//+-------------------------------------------------------------
void insertTail(struct node **headRef, struct node *n){
struct node* newNode = malloc(sizeof(struct node)); //create and allocate space in memory for a new node called newNode
newNode = *headRef; //the new node is now the head reference
while(newNode->next != NULL) //while the next node is not equal NULL
newNode = newNode->next; //set the newNode to the next node (this finds the last node)
struct node* tmp = malloc(sizeof(struct node)); //create and allocate space in memory for a new node called tmp
tmp->item = n->item; //the data of tmp is assigned the data of the parameter node 'n'
tmp->next = NULL; //the node following tmp is set to NULL
newNode->next = tmp; //tmp is now set to the next node, thus, becoming the last node i.e. the tail
}
//+-------------------------------------------------------------
//+ COUNT NODES IN LINKED LIST
//+
//+ Count the # of nodes that are part of the LinkedList.
//+-------------------------------------------------------------
int countNodes(struct node *headRef){
int counter = 0; //create a counter variable to store the number of nodes
struct node* current = headRef; //create a new node and assign it the reference to the head node
if(headRef = NULL) return 0; //if the head is NULL, return 0 (no nodes if no head)
while(current != NULL){ //while the current node is not NULL
counter++; //increment the counter
current = current->next; //and move on to the next node, thus, adding 1 to the counter with each node passed
}
return counter; //return the total number of nodes, stored in counter
}
//+-------------------------------------------------------------
//+ FIND NODE
//+
//+ Return the first node that has item = val, return NULL
//+ otherwise.
//+-------------------------------------------------------------
struct node* findNode(struct node *head, int val){
struct node* tmp = malloc(sizeof(struct node)); //create and allocate space in memory for a new node called tmp
*tmp = *head; //node tmp is now referring to the head node of the list
while(tmp != NULL) //while the tmp node is not equal to NULL
{
if(tmp->item == val){ //if the data of the tmp node is equal to the value sent as parameter
return tmp; //return the tmp node
}else{
return NULL; //otherwise, return NULL
}
tmp = tmp->next; //set the tmp node to the next node in the list (traversing)
}
}
//+-------------------------------------------------------------
//+ DELETE NODE
//+
//+ Delete node n from the list and free memory allocated to n.
//+-------------------------------------------------------------
void deleteNode(struct node **headRef, struct node *n){
struct node* toBeDeletedNode = malloc(sizeof(struct node)); //create and allocate space in memory for a new node called toBeDeletedNode
toBeDeletedNode = findNode(*headRef, n->item); //toBeDeletedNode is set to equal the node findNode() returns
//this node should be the node with its data = to the data of the parameter node n
free(toBeDeletedNode); //delete node toBeDeletedNode references and free the space allocated it
}
这是测试文件....
#include "list.h"
#include <assert.h>
#include <sys/types.h>
#include <stdio.h>
// create and insertHead
void test1()
{
struct node *headRef=NULL;
struct node *nptr = NULL;
int h=0;
while(h<5)
insertHead(&headRef,createNode(h++));
h = 0;
for (nptr = headRef; nptr != NULL; nptr = nptr->next, h++)
assert(nptr->item == (4 - h) );
assert(h==5);
printf("HAHA");
}
// create and insertTail
void test2()
{
struct node *headRef=NULL;
struct node *nptr = NULL;
int h=0, t=0;
while(h<5)
insertTail(&headRef,createNode(h++));
h = 0;
for (nptr = headRef; nptr != NULL; nptr = nptr->next, h++)
assert(nptr->item == h);
assert(h==5);
printf("HAHA");
}
// countNodes
void test3()
{
struct node *headRef=NULL;
struct node *nptr = NULL;
int h=0, t=0;
while(h<50)
insertTail(&headRef,createNode(h++));
h = 0;
for (nptr = headRef; nptr != NULL; nptr = nptr->next, h++)
assert(nptr->item == h);
assert(countNodes(headRef) == 50);
}
// findNode
void test4()
{
struct node *headRef=NULL;
struct node *nptr = NULL;
int h=0;
nptr = findNode(headRef, 1);
assert(nptr == NULL);
while(h<50)
insertTail(&headRef,createNode(h++));
nptr = findNode(headRef, 10);
assert(nptr != NULL);
assert (nptr->item = 10);
nptr = findNode(headRef, -10);
assert(nptr == NULL);
}
// deleteNode
void test5()
{
struct node *headRef=NULL;
struct node *nptr = NULL;
int h=0;
while(h<5)
insertTail(&headRef,createNode(h++));
h = 0;
while(h<5) {
nptr = findNode(headRef, h);
assert(nptr != NULL);
deleteNode(&headRef, nptr);
assert(findNode(headRef, h) == NULL);
assert(countNodes(headRef) == (4 - h));
h++;
}
}
/*// sort
void test6()
{
struct node *headRef=NULL;
struct node *nptr = NULL;
int h=0;
int d[5] = {1, 0, -1, 5, 100};
int ds[5] = {-1, 0, 1, 5, 100};
while(h<5)
insertTail(&headRef,createNode(d[h++]));
sort(&headRef);
h = 0;
for (nptr = headRef; nptr != NULL; nptr = nptr->next, h++)
assert(nptr->item == ds[h]);
}*/
int main( int argc, char ** argv )
{
int testNum = 0;
if ( argc < 2 ) {
fprintf(stderr, "\n usage: %s test-num\n", argv[0]);
return 1;
}
testNum = atoi(argv[1]);
switch(testNum){
case 1:
test1();
break;
case 2:
test2();
break;
case 3:
test3();
break;
case 4:
test4();
break;
case 5:
test5();
break;
case 6:
//test6();
break;
default:
fprintf(stderr, "\n usage: %s 1 .. 8\n", argv[0]);
return 1;
}
return 0;
}
最佳答案
我不知道这是不是错误,但这行几乎可以肯定是错误的:
if(headRef = NULL) return 0; //if the head is NULL, return 0 (no nodes if no head)
应该是
if(headRef == NULL) return 0; //if the head is NULL, return 0 (no nodes if no head)
它在 countNodes()
中。
关于c - C 中的段错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/4821013/