malloc到新的 [英] malloc to new
问题描述
我正在尝试在C ++中使用new / delete而不是malloc / free。
我有这个：
int g_TTable_size = 130000; //例如
struct hash_t
{
int深度;
int flags;
int eval;
};
这样可以正常工作：
hash_t * pt_htable =（hash_t *）malloc （g_TTable_size * sizeof（hash_t））;
if（pt_htable！= NULL）{free（pt_htable）;}
但这不是： - （（（
hash_t * pt_htable =（hash_t *）new char [g_TTable_size * sizeof（hash_t）];
both：
hash_t * pt_htable =（ hash_t *）new hash_t [g_TTable_size];
这可能没问题，我还不知道：
if（pt_htable！= NULL）{delete pt_htable; }
我做错了什么？
感谢您的帮助。
" Jeff"< no **** @ nospam.com>写在留言中
news：41 ***** ****************** @ news.wanadoo.fr ...
我正在尝试在C ++中使用new / delete而不是malloc / free 。
我有这个：
int g_TTable_size = 130000; //例如
struct hash_t
{int int;
int flags;
int eval;
};
这很好用：
hash_t * pt_htable =（hash_t *）malloc（g_TTable_size * sizeof（hash_t））;
if（pt_htable！= NULL）{free（pt_htable）;}
<但是这不是： - （（
hash_t * pt_htable =（hash_t *）new char [g_TTable_size * sizeof（hash_t）];
既不：
hash_t * pt_htable =（hash_t * ）new hash_t [g_TTable_size];
这可能没问题，我还不知道：
if（pt_htable！= NULL）{delete pt_htable;}
什么我做错了吗？
你没有使用可用的工具：
#include< vector>
std :: vector< hash_t> htable（g_TTable_size）;
Jeff
Jeff写道：我正在尝试在C ++中使用new / delete而不是malloc / free。
我有这个：
int g_T Table_size = 130000; //例如
struct hash_t
{int int;
int flags;
int eval;
};
这很好用：
hash_t * pt_htable =（hash_t *）malloc（g_TTable_size * sizeof（hash_t））;
if（pt_htable！= NULL）{free（pt_htable）;}
<但是这不是： - （（
hash_t * pt_htable =（hash_t *）new char [g_TTable_size * sizeof（hash_t）];
a）没有必要投下结果。放弃演员。
b）大小错误。括号中的表达式不应该是''sizeof''部分。
both：
hash_t * pt_htable =（hash_t *）new hash_t [g_TTable_size ]。
a）这个尺寸更好。但仍然，放弃该死的演员。
这可能没问题，我还不知道：
if（pt_htable！= NULL）{delete pt_htable;}
不，这不行。如果使用''new []''进行分配，则需要使用
delete []。此外，如果分配失败，则抛出异常，除非使用''nothrow''变体，否则''new''
不会返回NULL。只需说
删除[] pt_htable;
我做错了什么？
你你可能不会仔细阅读你的C ++书籍。
V
Jeff发布：
我正在尝试在C ++中使用new / delete而不是malloc / free。
我有这个：
int g_TTable_size = 130000; //例如
struct hash_t
{int int;
int flags;
int eval;
};
这很好用：
hash_t * pt_htable =（hash_t *）malloc（g_TTable_size * sizeof（hash_t））;
if（pt_htable！= NULL）{free（pt_htable）;}
<但是这不是： - （（
hash_t * pt_htable =（hash_t *）new char [g_TTable_size * sizeof（hash_t）];
既不：
hash_t * pt_htable =（hash_t * ）new hash_t [g_TTable_size];
这可能没问题，我还不知道：
if（pt_htable！= NULL）{delete pt_htable;}
hash_t * pt_htablearray1 = new hash_t [g_TTable_size];
delete [] pt_htablearray;
hash_t * pt_htablearray2 = reinterpret_cast< hash_t * const>（new char
[g_TTable_size * sizeof（hash_t）]）;
delete [] pt_htablearray2;
-JKop
Hi,
i''m trying to use new/delete in C++ instead of malloc/free.
I have this :
int g_TTable_size=130000; // for example
struct hash_t
{
int depth;
int flags;
int eval;
};
And this works fine :
hash_t *pt_htable = (hash_t *) malloc (g_TTable_size*sizeof(hash_t));
if(pt_htable!=NULL) {free(pt_htable);}
But this not :-((
hash_t *pt_htable = (hash_t *) new char[g_TTable_size*sizeof(hash_t)];
neither :
hash_t *pt_htable = (hash_t *) new hash_t[g_TTable_size];
And this may be ok, i don''t know yet :
if(pt_htable!=NULL) {delete pt_htable;}
What am i doing wrong ?
Thanks for your help.
"Jeff" <no****@nospam.com> wrote in message
news:41***********************@news.wanadoo.fr...Hi,
i''m trying to use new/delete in C++ instead of malloc/free.
I have this :
int g_TTable_size=130000; // for example
struct hash_t
{
int depth;
int flags;
int eval;
};
And this works fine :
hash_t *pt_htable = (hash_t *) malloc (g_TTable_size*sizeof(hash_t));
if(pt_htable!=NULL) {free(pt_htable);}
But this not :-((
hash_t *pt_htable = (hash_t *) new char[g_TTable_size*sizeof(hash_t)];
neither :
hash_t *pt_htable = (hash_t *) new hash_t[g_TTable_size];
And this may be ok, i don''t know yet :
if(pt_htable!=NULL) {delete pt_htable;}
What am i doing wrong ?
Your not using the available tools:
#include <vector>
std::vector<hash_t> htable( g_TTable_size );
Jeff
Jeff wrote:i''m trying to use new/delete in C++ instead of malloc/free.
I have this :
int g_TTable_size=130000; // for example
struct hash_t
{
int depth;
int flags;
int eval;
};
And this works fine :
hash_t *pt_htable = (hash_t *) malloc (g_TTable_size*sizeof(hash_t));
if(pt_htable!=NULL) {free(pt_htable);}
But this not :-((
hash_t *pt_htable = (hash_t *) new char[g_TTable_size*sizeof(hash_t)];
a) There is no need to cast the result. Drop the cast.
b) The size if wrong. The expression in the brackets should not have
the ''sizeof'' part.
neither :
hash_t *pt_htable = (hash_t *) new hash_t[g_TTable_size];
a) This is better size-wise. But still, drop the damn cast.
And this may be ok, i don''t know yet :
if(pt_htable!=NULL) {delete pt_htable;}
No, this is not OK. If you allocate using ''new[]'', you need to use
delete[]. Also, if allocation fails, an exception is thrown, the ''new''
does not return NULL unless you use the ''nothrow'' variation. Just say
delete[] pt_htable;
What am i doing wrong ?
You''re probably not reading your C++ book as carefully as you should.
V
Jeff posted:
Hi,
i''m trying to use new/delete in C++ instead of malloc/free.
I have this :
int g_TTable_size=130000; // for example
struct hash_t
{
int depth;
int flags;
int eval;
};
And this works fine :
hash_t *pt_htable = (hash_t *) malloc (g_TTable_size*sizeof(hash_t));
if(pt_htable!=NULL) {free(pt_htable);}
But this not :-((
hash_t *pt_htable = (hash_t *) new char[g_TTable_size*sizeof(hash_t)];
neither :
hash_t *pt_htable = (hash_t *) new hash_t[g_TTable_size];
And this may be ok, i don''t know yet :
if(pt_htable!=NULL) {delete pt_htable;}
hash_t *pt_htablearray1 = new hash_t[g_TTable_size];
delete [] pt_htablearray;
hash_t *pt_htablearray2 = reinterpret_cast<hash_t* const>( new char
[g_TTable_size * sizeof(hash_t)] );
delete [] pt_htablearray2;
-JKop
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