如果一个数组空间太小了，要分配一个大数组......

[nothing707]

如何来分配一个新的、更大的数组，然后把前一个小数组，复制到大数组上去。
释放小数组所占的空间。想了半天没有想出来，敬听各位高见。

[北极猩猩]

在C++中没有特殊要求的话干脆使用vector算了，根本不需要考虑空间够不够的问题

[brave_heart]

/* 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 <stdio.h>
#include <malloc.h>
#include <stdlib.h>

void 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 );
}

[earthharp]

realloc或者
重新new 一个数组再使用memmove或者memcpy.

[nothing707]

earthharp:
你也来个例子呀~

[fangrk]

用vector

[nothing707]

要例子fangrk:)

[earthharp]

#include <iostream>
#include <iomanip>
#include <vector>
#include <functional>
#include <cstdio>
#include <cstdlib>
#include <algorithm>


using namespace std;


void Print(int a)
{
std::cout << a << " ";
}
int main()
{
int* pi = reinterpret_cast<int*>(malloc(100 * sizeof(int)));
*pi = 1;
pi = reinterpret_cast<int*>(realloc(pi, 1000 * sizeof(int)));

std::cout << *pi << std::endl;
free(pi);

vector<int> vi;
vi.push_back(33);
vi.push_back(22);
vi.push_back(11);
vi.push_back(2356);

vi.resize(200, 0);

for_each(vi.begin(), vi.end(), Print);
}

[sunriselx]

用stl的容器，插入时自动在堆上分配内存