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Single quotes vs. double quotes in C or C++
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In C and in C++ single quotes identify a single character, while double quotes create a string literal. 'a' is a single a character literal, while "a" is a string literal containing an 'a' and a null terminator (that is a 2 char array).
In C++ the type of a character lite...
How can I validate a string to only allow alphanumeric characters in it?
...n I validate a string using Regular Expressions to only allow alphanumeric characters in it?
10 Answers
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Base64 length calculation?
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Each character is used to represent 6 bits (log2(64) = 6).
Therefore 4 chars are used to represent 4 * 6 = 24 bits = 3 bytes.
So you need 4*(n/3) chars to represent n bytes, and this needs to be rounded up to a multiple of 4.
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Java: parse int value from a char
I just want to know if there's a better solution to parse a number from a character in a string (assuming that we know that the character at index n is a number).
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Unmangling the result of std::type_info::name
...clude <string>
#include <typeinfo>
std::string demangle(const char* name);
template <class T>
std::string type(const T& t) {
return demangle(typeid(t).name());
}
#endif
In file type.cpp (requires C++11)
#include "type.hpp"
#ifdef __GNUG__
#include <cstdlib>
#in...
iterating over each character of a String in ruby 1.8.6 (each_char)
I am new to ruby and currently trying to operate on each character separately from a base String in ruby. I am using ruby 1.8.6 and would like to do something like:
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Best way to serialize an NSData into a hexadeximal string
... string of NSData. Empty string if data is empty. */
const unsigned char *dataBuffer = (const unsigned char *)[self bytes];
if (!dataBuffer)
return [NSString string];
NSUInteger dataLength = [self length];
NSMutableString *hexString = [NSMutableString stri...
What does int argc, char *argv[] mean?
...ention, but they can be given any valid identifier: int main(int num_args, char** arg_strings) is equally valid.
They can also be omitted entirely, yielding int main(), if you do not intend to process command line arguments.
Try the following program:
#include <iostream>
int main(int argc,...
What is the difference between static_cast and C style casting?
...situations where all that is needed is a simple conversion. The ability to select between several different casting operators of differing degrees of power can prevent programmers from inadvertently casting to an incorrect type.
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Difference between BYTE and CHAR in column datatypes
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Let us assume the database character set is UTF-8, which is the recommended setting in recent versions of Oracle. In this case, some characters take more than 1 byte to store in the database.
If you define the field as VARCHAR2(11 BYTE), Oracle can us...