作者：与天使有染的救赎_164 | 来源：互联网 | 2023-09-09 11:01
兄弟们,问一个很弱的问题,谁有空请指教!在线等我想把一个纯文本文件中的所有行(行数不定,任意行)读到一个字符数组中去,如何写?要把一行一行的内容依次连接到一个char*buf
兄弟们,问一个很弱的问题,谁有空请指教!在线等
我想把一个纯文本文件中的所有行(行数不定,任意行)读到一个字符数组中去,如何写?
要把一行一行的内容依次连接到一个char *buf中,不能用数组,因为行数不定
我是这样写的
char *buf_requ, *buf_reps, *pRequ, *pReps;
pRequ = buf_requ ;pReps = buf_reps ; // 保存指针首地址
while ( !feof( fp ) ) {
fputs( buffer, fp2 );
buf_reps = ( char * )malloc( lineLen + 1 );
assert( buf_reps != NULL );
memset(buf_reps, 0, lineLen );
strcat( buf_reps, buffer ); // 好象指针首地址丢了
}
这样每次malloc的地址不是连续的,所以strcat不能连接上是不?
但又应该如何解决呢?
4 个解决方案
用vector 每一行都读取放入到其中,用法简单,操作容易
这样会后问题的，因为每次分配的地址不同，你可以先读入，最后根据总的长度再分配一次。
strcat( buf_reps, buffer ); //不用你为他分配内存
char *buf_requ, *buf_reps, *pRequ, *pReps; //buf_requ, buf_reps要分配内存给他
fputs( buffer, fp2 );//这个不是读文件内容
看不懂你的程序想要表达的意思
你究竟想做什么的？
reallocSee Also
Memory Allocation Routines | calloc | free | malloc | Run-Time Routines and .NET Framework Equivalents
Requirements
Routine Required header Compatibility
realloc and ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP
For additional compatibility information, see Compatibility in the Introduction.
Libraries
All versions of the C run-time libraries.
Reallocate memory blocks.
void *realloc(
void *memblock,
size_t size
);
Parameters
memblock
Pointer to previously allocated memory block.
size
New size in bytes.
Return Value
realloc returns a void pointer to the reallocated (and possibly moved) memory block. The return value is NULL if the size is zero and the buffer argument is not NULL, or if there is not enough available memory to expand the block to the given size. In the first case, the original block is freed. In the second, the original block is unchanged. The return value points to a storage space that is guaranteed to be suitably aligned for storage of any type of object. To get a pointer to a type other than void, use a type cast on the return value.
Remarks
The realloc function changes the size of an allocated memory block. The memblock argument points to the beginning of the memory block. If memblock is NULL, realloc behaves the same way as malloc and allocates a new block of size bytes. If memblock is not NULL, it should be a pointer returned by a previous call to calloc, malloc, or realloc.
The size argument gives the new size of the block, in bytes. The contents of the block are unchanged up to the shorter of the new and old sizes, although the new block can be in a different location. Because the new block can be in a new memory location, the pointer returned by realloc is not guaranteed to be the pointer passed through the memblock argument.
realloc calls malloc in order to use the C++ _set_new_mode function to set the new handler mode. The new handler mode indicates whether, on failure, malloc is to call the new handler routine as set by _set_new_handler. By default, malloc does not call the new handler routine on failure to allocate memory. You can override this default behavior so that, when realloc fails to allocate memory, malloc calls the new handler routine in the same way that the new operator does when it fails for the same reason. To override the default, call
_set_new_mode(1)
early in your program, or link with NEWMODE.OBJ.
When the application is linked with a debug version of the C run-time libraries, realloc resolves to _realloc_dbg. For more information about how the heap is managed during the debugging process, see The CRT Debug Heap.
Requirements
Routine Required header Compatibility
realloc and ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP
For additional compatibility information, see Compatibility in the Introduction.
Libraries
All versions of the C run-time libraries.
Example
// crt_realloc.c
/* This program allocates a block of memory for
* buffer and then uses _msize to display the size of that
* block. Next, it uses realloc to expand the amount of
* memory used by buffer and then calls _msize again to
* display the new amount of memory allocated to buffer.
*/
#include
#include
#include
int main( void )
{
long *buffer;
size_t size;
if( (buffer = (long *)malloc( 1000 * sizeof( long ) )) == NULL )
exit( 1 );
size = _msize( buffer );
printf( "Size of block after malloc of 1000 longs: %u\n", size );
/* Reallocate and show new size: */
if( (buffer = realloc( buffer, size + (1000 * sizeof( long )) ))
== NULL )
exit( 1 );
size = _msize( buffer );
printf( "Size of block after realloc of 1000 more longs: %u\n",
size );
free( buffer );
exit( 0 );
}
Output
Size of block after malloc of 1000 longs: 4000
Size of block after realloc of 1000 more longs: 8000
See Also
Memory Allocation Routines | calloc | free | malloc | Run-Time Routines and .NET Framework Equivalents
--------------------------------------------------------------------------------
Send feedback on this topic to Microsoft
© Microsoft Corporation. All rights reserved.
京公网安备 11010802041100号