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What is the difference between char * const and const char *?
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The difference is that const char * is a pointer to a const char, while char * const is a constant pointer to a char.
The first, the value being pointed to can't be changed but the pointer can be. The second, the value being pointed at can change but t...
C pointers : pointing to an array of fixed size
... an array to a function is by using a pointer-to-array parameter
void foo(char (*p)[10]);
(in C++ language this is also done with references
void foo(char (&p)[10]);
).
This will enable language-level type checking, which will make sure that the array of exactly correct size is supplied a...
std::wstring VS std::string
...s between std::string and std::wstring . I know wstring supports wide characters such as Unicode characters. I have got the following questions:
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Why unsigned integer is not available in PostgreSQL?
...< 65536);
Here is what psql gives when I try to abuse the type.
DS1=# select (346346 :: uint2);
ERROR: value for domain uint2 violates check constraint "uint2_check"
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Length of string in bash
...NG=C LC_ALL=C
bytlen=${#myvar}
LANG=$oLang LC_ALL=$oLcAll
printf "%s is %d char len, but %d bytes len.\n" "${myvar}" $chrlen $bytlen
will render:
Généralités is 11 char len, but 14 bytes len.
you could even have a look at stored chars:
myvar='Généralités'
chrlen=${#myvar}
oLang=$LANG oLc...
Get string character by index - Java
I know how to work out the index of a certain character or number in a string, but is there any predefined method I can use to give me the character at the nth position? So in the string "foo", if I asked for the character with index 0 it would return "f".
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C: differences between char pointer and array [duplicate]
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True, but it's a subtle difference. Essentially, the former:
char amessage[] = "now is the time";
Defines an array whose members live in the current scope's stack space, whereas:
char *pmessage = "now is the time";
Defines a pointer that lives in the current scope's stack space, b...
How to convert a char array to a string?
Converting a C++ string to a char array is pretty straightorward using the c_str function of string and then doing strcpy . However, how to do the opposite?
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MYSQL Truncated incorrect DOUBLE value
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Same issue for me. A 'select * from t where id = 6503' worked okay but 'update t set a = "foo" where id = 6503' resulted in ERROR 1292 (22007): Truncated incorrect DOUBLE value: '234805557438#'. id looks like integer but was a varchar. Quoting th...
Returning a C string from a function
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Your function signature needs to be:
const char * myFunction()
{
return "My String";
}
Background:
It's so fundamental to C & C++, but little more discussion should be in order.
In C (& C++ for that matter), a string is just an array of bytes terminate...