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Concept of void pointer in C programming
...l incorrectly, you can safely dereference a void* in two ways. Casting to char* is always acceptable, and if you know the original type it points to you can cast to that type. The void* has lost the type info so it'd have to be stored elsewhere.
– Dan Olson
M...
What's the difference between a file descriptor and file pointer?
...LE Structure returned by fopen
typedef struct
{
unsigned char *_ptr;
int _cnt;
unsigned char *_base;
unsigned char *_bufendp;
short _flag;
short _file;
int __stdioid;
char *__newbase;
#ifdef _THREAD_SAFE
...
How to get rid of punctuation using NLTK tokenizer?
...ample, you can define a tokenizer that picks out sequences of alphanumeric characters as tokens and drops everything else:
from nltk.tokenize import RegexpTokenizer
tokenizer = RegexpTokenizer(r'\w+')
tokenizer.tokenize('Eighty-seven miles to go, yet. Onward!')
Output:
['Eighty', 'seven', 'mil...
Difference: std::runtime_error vs std::exception()
... not standard. The runtime_error class has a constructor taking arguments (char*) on both platforms, Windows and Linux. To be portable, better use runtime_error.
(And remember, just because a specification of your project says your code does not have to run on Linux, it does not mean it does never ...
Difference between a Structure and a Union
...re that value.
union foo {
int a; // can't use both a and b at once
char b;
} foo;
struct bar {
int a; // can use both a and b simultaneously
char b;
} bar;
union foo x;
x.a = 3; // OK
x.b = 'c'; // NO! this affects the value of x.a!
struct bar y;
y.a = 3; // OK
y.b = 'c'; // OK
ed...
Are there any downsides to passing structs by value in C, rather than passing a pointer?
...e output parameters be listed first before input parameters, e.g. int func(char* out, char *in);
– zooropa
Apr 29 '09 at 12:29
...
What's the most efficient test of whether a PHP string ends with another string?
...slower due to more testing.
Probably the most efficient way is to do loop char-by-char from the -sterlen(test) position till the end of the string and compare. That's the minimal amount of comparisons you can hope to do and there's hardly any extra memory used.
...
Why is “a” != “a” in C?
...strings at compile time into one to save space.
When you're comparing two character values (which are not pointers), it is a numeric comparison. For example:
'a' == 'a' // always true
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imp...
与复制构造函数相关的错误.例如:0x77D9FCAA (ntdll.dll) (prog31.exe 中)处...
...含指针成员，没有复制构造函数出错
struct Node
{
Node(char *n="",int a = 0)
{
name = strdup(n);
strcpy(name,n);
age = a ;
}
~Node()
{
delete[] name;
}
char *name;
int age;
};
int main()
{
Node node1("Roger",20),node2(node1);
//pri...
How to disable GCC warnings for a few lines of code
...ing puts.c source code
#include <stdio.h>
int main(int argc, const char *argv[])
{
while (*++argv) puts(*argv);
return 0;
}
It will not compile because argc is unused, and the settings are hardcore (-W -Wall -pedantic -Werror).
There are 5 things you could do:
Improve the source...