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Are there disadvantages to using a generic varchar(255) for all text-based fields?
...e , town , country , phone number etc, all of which are defined as VARCHAR(255) even though none of these fields will ever come close to having 255 characters. (If you're wondering, it's this way because Ruby on Rails migrations map String fields to VARCHAR(255) by default and I never bothe...
c语言字符串常量内容是否可以通过指针修改 - C/C++ - 清泛网 - 专注C/C++及内核技术
...是：不行。尝试修改的话，运行时程序会崩溃。int main(){ char str1[40]="hello world!"; char *str1="hello world!"...答案是：不行。尝试修改的话，运行时程序会崩溃。
int main()
{
char str1[40]="hello world!"; //char *str1="hello world!";
str1[4]...
c/c++如何判断指针无效？如NULL,0xcccccccc,0xfeeefeee,野指针等 - C/C++ -...
...何判断指针是否有效呢？
AfxIsValidAddress
// Allocate a 5 character array, which should have a valid memory address.
char* arr = new char[5];
// Create a null pointer, which should be an invalid memory address.
char* null = (char*)0x0;
ASSERT(AfxIsValidAddress(arr, 5));
ASSE...
C/C++获取Windows的CPU、内存、硬盘使用率 - C/C++ - 清泛网 - 专注C/C++及内核技术
...icalDriveStrings()函数获取所有驱动器字符串信息长度。
char* DStr = new char[DSLength];//用获取的长度在堆区创建一个c风格的字符串数组
GetLogicalDriveStrings(DSLength, (LPTSTR)DStr);
//通过GetLogicalDriveStrings将字符串信息复制到堆区数...
【解决】munmap_chunk(): invalid pointer - C/C++ - 清泛网 - 专注C/C++及内核技术
...指针被覆盖掉了，然后delete free就会报这个错误。例如：char* word = (char*)malloc(10);word = "abc"; 应使用 strcpy(word, "abc");free(word) 原因：new/malloc出来的指针被覆盖掉了，然后delete/free就会报这个错误。
例如：
char* word = (char*)malloc(1...
application/x-www-form-urlencoded or multipart/form-data?
...will fail.
The key is to choose an encoding and a boundary such that your selected boundary characters cannot appear in the encoded output. One simple solution is to use base64 (do not use raw binary). In base64 3 arbitrary bytes are encoded into four 7-bit characters, where the output character se...
Passing an array by reference
...an be passed by reference OR by degrading to a pointer. For example, using char arr[1]; foo(char arr[])., arr degrades to a pointer; while using char arr[1]; foo(char (&arr)[1]), arr is passed as a reference. It's notable that the former form is often regarded as ill-formed since the dimension...
Allowed characters in filename [closed]
Where can I find a list of allowed characters in filenames, depending on the operating system?
(e.g. on Linux, the character : is allowed in filenames, but not on Windows)
...
LINQ equivalent of foreach for IEnumerable
...d evaluating Funcs
var evaluatedObservable = observable.ToEnumerable().Select(func => func()).ToList();
//Win
Assert.That(evaluatedObservable,
Is.EquivalentTo(values.ToList()));
}
The following fails with the error:
Expected: equivalent to < 0, 1, 2, 3, 4, 5, 6, 7, 8, ...
How to remove spaces from a string using JavaScript?
...
split(' ') and join won't remove \n , \t white space chars, another workaround is a.split('').map(c =>c.trim()).join('')
– rab
Apr 18 '19 at 10:40
ad...