运行出来应该是这样的,第一个输的是n,就是从后往前数第几个元素,然后输入的是总共的元素。
//这是我写的,不知道哪有问题
int get_nth_last(int n, struct node *head) {
struct node *p;
p = head;
while (p->next == NULL) {
int i = p->data;
return i;
}
int i = 0;
while (p != NULL) {
p = p->next;
i++;
}
while (i - n > 0) {
head = head->next;
}
int number = head->data;
return number;
}
//这些代码不用改
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
struct node {
struct node *next;
int data;
};
int get_nth_last(int n, struct node *head);
struct node *strings_to_list(int len, char *strings[]);
// DO NOT CHANGE THIS MAIN FUNCTION
int main(int argc, char *argv[]) {
if (argc < 2) {
fprintf(stderr, "Usage: %s n list-elements\n", argv[0]);
return 1;
}
int n = atoi(argv[1]);
// create linked list from command line arguments
struct node *head = strings_to_list(argc - 2, &argv[2]);
int result = get_nth_last(n, head);
printf("%d\n", result);
return 0;
}
// DO NOT CHANGE THIS FUNCTION
// create linked list from array of strings
struct node *strings_to_list(int len, char *strings[]) {
struct node *head = NULL;
for (int i = len - 1; i >= 0; i = i - 1) {
struct node *n = malloc(sizeof (struct node));
assert(n != NULL);
n->next = head;
n->data = atoi(strings[i]);
head = n;
}
return head;
}