如何从输入中存储未知数量的未知长度字符串数组？

Question

我无法将输入的字符串存储到数组中。我想从以 EOF 结尾的输入中存储它，并且能够存储任意数量的任意长度的字符串。这是我的代码：

char **list = (char**)malloc(sizeof(char*));
char c = getchar();
int i, j, count = 0;
int size = 0;
char * string = NULL
while (c != EOF)
{
    size = 0;
    while (c != EOF && c != '\n')
    {
        string = (char*)realloc(string,size+1); //line 210
        string[size] = c;
        size++;
        c = getchar();
    }
    list = (char**)realloc(list, (count+1)*sizeof(char*));
    list[count] = string;
    ++count;
    string = NULL;
    c = getchar();
}
for (j = 0; j < count; ++j) //trying to print out all the strings
{
    printf("%s\n", list[j]); //line 237
}
free(string);
free(list);
return (EXIT_SUCCESS);

我知道我还应该测试所有分配是否成功，但这不是我现在的问题。该程序在使用 gcc -Wall -pedantic 编译时工作正常，但 valgrind 给出以下错误：

==2601== Memcheck, a memory error detector
==2601== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==2601== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==2601== Command: ./a.out -g
==2601== 
asd
dsa
==2601== Invalid read of size 1
==2601==    at 0x4C30F74: strlen (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==2601==    by 0x4EA95DB: puts (ioputs.c:35)
==2601==    by 0x4008E8: main (testing.c:237)
==2601==  Address 0x52035c3 is 0 bytes after a block of size 3 alloc'd
==2601==    at 0x4C2FD5F: realloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==2601==    by 0x40080D: main (testing.c:210)
==2601== 
asd
dsa
==2601== 
==2601== HEAP SUMMARY:
==2601==     in use at exit: 12 bytes in 4 blocks
==2601==   total heap usage: 14 allocs, 10 frees, 2,101 bytes allocated
==2601== 
==2601== LEAK SUMMARY:
==2601==    definitely lost: 12 bytes in 4 blocks
==2601==    indirectly lost: 0 bytes in 0 blocks
==2601==      possibly lost: 0 bytes in 0 blocks
==2601==    still reachable: 0 bytes in 0 blocks
==2601==         suppressed: 0 bytes in 0 blocks
==2601== Rerun with --leak-check=full to see details of leaked memory
==2601== 
==2601== For counts of detected and suppressed errors, rerun with: -v
==2601== ERROR SUMMARY: 2 errors from 1 contexts (suppressed: 0 from 0)

Answer 1

您需要释放为您读取的每个字符串分配的内存，而不是在程序末尾 freeing string：

for (j = 0; j < count; j++)    
        free(list[j]);
free(list);

要修复 "Invalid read of size 1" 错误，您需要更改：

string = realloc(string,size+2);

您正在使用 size 作为 string 的索引，因此您需要在为分配中的“\0”添加 space 之前增加此值。更好的变量名将有助于避免这个问题。考虑将 size 更改为 index.

另请注意，您需要 c 成为 int 才能存储 EOF 字符，因此请更改：

int c = getchar();

此外，此代码无法以 NUL 终止字符串。您需要添加：

...
string[size] = '[=13=]';    // NUL terminate string

list = realloc(list, (count+1)*sizeof(*list));
...

当你在程序开头初始化 list 时，还没有必要分配 space，你只是最终 reallocing 它，所以：

char **list = NULL;

请注意，我从对 malloc() 和 realloc() 的调用中删除了强制转换。这些在 C 中不需要，并且主要用于使代码混乱。同样，这里我没有使用sizeof(char*)，而是使用了sizeof(*list)，这样更不容易出错，也更加清晰。

如何从输入中存储未知数量的未知长度字符串数组？

How to store an array of an unknown amount of strings of unknown length from input?

c

valgrind

c89