blocks|key|1123162|text|假设您确实想要一个数组，而不是std::vector，那么"C%2B%2B方式“应该是这样的|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1123163|#include+<algorithm>+

int*+array+=+new+int[n];+//+Assuming+"n"+is+a+pre-existing+variable

std::fill_n(array,+n,+0);+|code-block|syntax|javascript|1123164|但请注意，在幕后，这实际上仍然只是一个将每个元素赋值为0的循环(除了具有硬件级支持的特殊体系结构之外，实际上没有其他方法可以做到这一点)。|1123165|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Assuming that you really do want an array and not a std::vector, the "C++ way" would be this

<pre><code>#include &lt;algorithm&gt; 

int* array = new int[n]; // Assuming "n" is a pre-existing variable

std::fill_n(array, n, 0); 
</code></pre>

But be aware that under the hood this is still actually just a loop that assigns each element to 0 (there's really not another way to do it, barring a special architecture with hardware-level support).

blocks|key|1123182|text|std::fill是一种方法。使用两个迭代器和一个值来填充区域。这，或者是for循环，(我想)将是更C%2B%2B的方式。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1123183|具体来说，对于将原始整数类型数组设置为0，memset是很好的，尽管它可能会令人惊讶。还要考虑calloc，尽管由于强制转换的原因，在C%2B%2B中使用它有点不方便。|1123184|对于我来说，我几乎总是使用循环。|1123185|(我不喜欢猜测人们的意图，但事实是，在所有条件相同的情况下，std::vector比使用new[]更可取。)|1123186|entityMap^0|0|9|0|L|6|1B|6|0|0|U|B|18|5|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|V|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|L|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|M|$]]

<code>std::fill</code> is one way. Takes two iterators and a value to fill the region with. That, or the for loop, would (I suppose) be the more C++ way.

For setting an array of primitive integer types to 0 specifically, <code>memset</code> is fine, though it may raise eyebrows. Consider also <code>calloc</code>, though it's a bit inconvenient to use from C++ because of the cast.

For my part, I pretty much always use a loop.

(I don't like to second-guess people's intentions, but it is true that <code>std::vector</code> is, all things being equal, preferable to using <code>new[]</code>.)

blocks|key|1338254|text|通常，对于项的动态列表，可以使用std::vector。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1338255|通常，我使用memset或循环进行原始内存动态分配，这取决于我对该代码区在未来的预期变量。|1338256|entityMap^0|G|B|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|M|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|N|8|@]|D|@]|E|$]]]|I|$]]

Typically for dynamic lists of items, you use a <code>std::vector</code>.

Generally I use memset or a loop for raw memory dynamic allocation, depending on how variable I anticipate that area of code to be in the future.

blocks|key|1338277|text|您可以始终使用memset：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1338278|int+myArray[10];
memset(+myArray,+0,+10+*+sizeof(+int+));|code-block|syntax|javascript|1338279|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

you can always use memset:

<pre><code>int myArray[10];
memset( myArray, 0, 10 * sizeof( int ));
</code></pre>

blocks|key|1338311|text|有许多方法来分配内部类型的数组，所有这些方法都是正确的，尽管选择哪一个取决于...|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1338312|循环中所有元素的手动初始化|1338313|int*+p+=+new+int[10];
for+(int+i+=+0;+i+<+10;+i%2B%2B)
++++p[i]+=+0;|code-block|syntax|javascript|1338314|使用<cstring>中的std::memset函数|offset|length|style|CODE|1338315|int*+p+=+new+int[10];
std::memset(p,+0,+sizeof+*p+*+10);|1338316|在<algorithm>中使用std::fill_n算法|1338317|int*+p+=+new+int[10];
std::fill_n(p,+10,+0);|1338318|使用std::vector容器|1338319|std::vector<int>+v(10);+//+elements+zero'ed|1338320|如果C%2B%2B11可用，请使用initializer+list功能|1338321|int+a[]+=+{+1,+2,+3+};+//+3-element+static+size+array
vector<int>+v+=+{+1,+2,+3+};+//+3-element+array+but+vector+is+resizeable+in+runtime|1338322|entityMap|0|LINK|mutability|MUTABLE|url|//en.cppreference.com/w/cpp/string/byte/memset|1|//en.cppreference.com/w/cpp/algorithm/fill_n|2|//en.cppreference.com/w/cpp/container/vector|3|//www.stroustrup.com/C%2B%2B11FAQ.html|4|//en.cppreference.com/w/cpp/utility/initializer_list^0|0|0|0|2|9|D|B|D|B|0|0|0|1|B|F|B|F|B|1|0|0|2|B|2|B|2|0|0|2|5|3|D|G|4|0|0^^$0|@$1|2|3|4|5|6|7|1I|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1J|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|1K|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|1L|8|@$K|1M|L|1N|M|N]|$K|1O|L|1P|M|N]]|9|@$K|1Q|L|1R|1|1S]]|A|$]]|$1|O|3|P|5|F|7|1T|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|1U|8|@$K|1V|L|1W|M|N]|$K|1X|L|1Y|M|N]]|9|@$K|1Z|L|20|1|21]]|A|$]]|$1|S|3|T|5|F|7|22|8|@]|9|@]|A|$G|H]]|$1|U|3|V|5|6|7|23|8|@$K|24|L|25|M|N]]|9|@$K|26|L|27|1|28]]|A|$]]|$1|W|3|X|5|F|7|29|8|@]|9|@]|A|$G|H]]|$1|Y|3|Z|5|6|7|2A|8|@]|9|@$K|2B|L|2C|1|2D]|$K|2E|L|2F|1|2G]]|A|$]]|$1|10|3|11|5|F|7|2H|8|@]|9|@]|A|$G|H]]|$1|12|3|-4|5|6|7|2I|8|@]|9|@]|A|$]]]|13|$14|$5|15|16|17|A|$18|19]]|1A|$5|15|16|17|A|$18|1B]]|1C|$5|15|16|17|A|$18|1D]]|1E|$5|15|16|17|A|$18|1F]]|1G|$5|15|16|17|A|$18|1H]]]]

There is number of methods to allocate an array of intrinsic type and all of these method are correct, though which one to choose, depends...
Manual initialisation of all elements in loop
<pre><code>int* p = new int[10];
for (int i = 0; i &lt; 10; i++)
 p[i] = 0;
</code></pre>
Using <a href="//en.cppreference.com/w/cpp/string/byte/memset" rel="nofollow noreferrer"><code>std::memset</code></a> function from <code>&lt;cstring&gt;</code>
<pre><code>int* p = new int[10];
std::memset(p, 0, sizeof *p * 10);
</code></pre>
Using <a href="//en.cppreference.com/w/cpp/algorithm/fill_n" rel="nofollow noreferrer"><code>std::fill_n</code></a> algorithm from <code>&lt;algorithm&gt;</code>
<pre><code>int* p = new int[10];
std::fill_n(p, 10, 0);
</code></pre>
Using <a href="//en.cppreference.com/w/cpp/container/vector" rel="nofollow noreferrer"><code>std::vector</code></a> container
<pre><code>std::vector&lt;int&gt; v(10); // elements zero'ed
</code></pre>
If <a href="//www.stroustrup.com/C++11FAQ.html" rel="nofollow noreferrer">C++11</a> is available, using <a href="//en.cppreference.com/w/cpp/utility/initializer_list" rel="nofollow noreferrer">initializer list</a> features
<pre><code>int a[] = { 1, 2, 3 }; // 3-element static size array
vector&lt;int&gt; v = { 1, 2, 3 }; // 3-element array but vector is resizeable in runtime
</code></pre>

blocks|key|1338340|text|初始化普通动态数组的可能方法。根据您的要求选择一个。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1338341|int*+x+=+new+int[5];++++++++++//+gv+gv+gv+gv+gv+(gv+-+garbage+value)
int*+x+=+new+int[5]();++++++++//+0++0++0++0++0+
int*+x+=+new+int[5]{};++++++++//+0++0++0++0++0++(Modern+C%2B%2B)
int*+x+=+new+int[5]{1,2,3};+++//+1++2++3++0++0++(Modern+C%2B%2B)|code-block|syntax|javascript|1338342|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Possible ways of initializing the plain dyanmic array. Choose the one as per your requirement.
<pre><code>int* x = new int[5]; // gv gv gv gv gv (gv - garbage value)
int* x = new int[5](); // 0 0 0 0 0 
int* x = new int[5]{}; // 0 0 0 0 0 (Modern C++)
int* x = new int[5]{1,2,3}; // 1 2 3 0 0 (Modern C++)
</code></pre>

I'm just beginning to get into C++ and I want to pick up some good habits. If I have just allocated an array of type <code>int</code> with the <code>new</code> operator, how can I initialise them all to 0 without looping through them all myself? Should I just use <code>memset</code>? Is there a &ldquo;C++&rdquo; way to do it?

How to initialise memory with new operator in C++?

容器

我刚刚开始接触C++，我想养成一些好习惯。如果我刚刚使用new操作符分配了一个int类型的数组，我如何才能在不亲自循环它们的情况下将它们全部初始化为0呢？我应该只使用memset吗？有没有一种“C++”的方式呢？

问如何在C++中用新运算符初始化内存？
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