c - 链表麻烦

Question

有谁知道下面的代码可能有什么问题？当我运行它时，我得到以下输出:

Insert a value in the list: 1
Do you want to continue? y/N: 
 1 ->

事实是do-while循环一直执行到scanf("%c", &ch)语句，然后跳出(所以我无法为提供任何输入ch 变量)。我尝试使用 GDB 进行调试，但收到了一些奇怪的消息:

GI___libc_malloc (bytes=16) at malloc.c:malloc.c: No such file or directory. 

另外，它说编译器找不到 vscanf.c 文件。有人对这种奇怪的行为有解释吗？谢谢! (目的是以相反的顺序打印单向链表的值。)

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

struct node{
    int info;
    struct node* next;
};

struct node* head = 0;

void add_node(int value){

     struct node* current = malloc(sizeof(struct node));
     current->info = value;
     current->next = head;
     head = current;
 }

void print_node(struct node* head){

     while(head){

          printf(" %d -> ", head->info);
          head = head->next;
     }

     printf("\n");
 }

int main(void){

    int val;
    char ch;

    do {

       printf("Insert a value in the list: ");
       scanf("%d", &val);
       add_node(val);
       printf("Do you want to continue? y/N: ");
       scanf("%c", &ch);

    } while(ch == 'y' || ch == 'Y');

    printf("\n");
    print_node(head);
    return 0;
 }

Answer 1

如果您希望输入以新行分隔(看起来您确实这样做了)，请更改您阅读角色的格式。更改如下:

scanf( "%c", &ch );

...为此:

scanf( "\n%c", &ch ); // << Note, \n to pickup newline before reading the value.