大约有 12,000 项符合查询结果（耗时：0.0272秒） [XML]
How do I check for nulls in an '==' operator overload without infinite recursion?
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Use ReferenceEquals:
Foo foo1 = null;
Foo foo2 = new Foo();
Assert.IsFalse(foo1 == foo2);
public static bool operator ==(Foo foo1, Foo foo2) {
if (object.ReferenceEquals(null, foo1))
return object.ReferenceEquals(null, foo2);
ret...
Try-finally block prevents StackOverflowError
...(2^N) where N is the maximum stack depth.
Imagine the maximum depth is 5
foo() calls
foo() calls
foo() calls
foo() calls
foo() which fails to call foo()
finally calls
foo() which fails to call foo()
finally
foo() calls
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【最全】CSS响应式布局的5种实现方式 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...大和缩小了
js 动态修改 html 根元素的 font-size 的大小，能适配不同尺寸的屏幕，不再局限于这 5 种
<script>
initPage();
function initPage() {
var clientWidth =
document.documentElement.clientWidth || document.body / clientWidth; //获取屏幕可视区宽
...
How to use C++ in Go
... have inheritance.
Here's an example:
I have a C++ class defined as:
// foo.hpp
class cxxFoo {
public:
int a;
cxxFoo(int _a):a(_a){};
~cxxFoo(){};
void Bar();
};
// foo.cpp
#include <iostream>
#include "foo.hpp"
void
cxxFoo::Bar(void){
std::cout<<this->a<<std::endl...
C# generic type constraint for everything nullable
...
If you are willing to make a runtime check in Foo's constructor rather than having a compile-time check, you can check if the type is not a reference or nullable type, and throw an exception if that's the case.
I realise that only having a runtime check may be unaccepta...
代码块超过1.2w编译apk报错问题 - App Inventor 2 中文网 - 清泛IT社区，为创新赋能！
...所有平台都是点编译就服务器错误。
只有code服务器，能通过，但是编译过程报错：
RequestTooLargeError 可能指的是事务任务列表的大小以及数据存储实体的大小，
不能超过 1 MB。您要添加的任务加上数据的总大小是多少？h...
How to create an object for a Django model with a many to many field?
...ginal suggestion. It works, but isn't optimal. (Note: I'm using Bars and a Foo instead of Users and a Sample, but you get the idea).
bar1 = Bar.objects.get(pk=1)
bar2 = Bar.objects.get(pk=2)
foo = Foo()
foo.save()
foo.bars.add(bar1)
foo.bars.add(bar2)
It generates a whopping total of 7 queries:
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What is the colon operator in Ruby?
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:foo is a symbol named "foo". Symbols have the distinct feature that any two symbols named the same will be identical:
"foo".equal? "foo" # false
:foo.equal? :foo # true
This makes comparing two symbols really fast (sin...
How to disallow temporaries
For a class Foo, is there a way to disallow constructing it without giving it a name?
10 Answers
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Looping over arrays, printing both index and value
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You would find the array keys with "${!foo[@]}" (reference), so:
for i in "${!foo[@]}"; do
printf "%s\t%s\n" "$i" "${foo[$i]}"
done
Which means that indices will be in $i while the elements themselves have to be accessed via ${foo[$i]}
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