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What does the explicit keyword mean?
...cidental construction that can hide bugs.
Contrived example:
You have a MyString(int size) class with a constructor that constructs a string of the given size. You have a function print(const MyString&), and you call print(3) (when you actually intended to call print("3")). You expect it to p...
Haskell: Lists, Arrays, Vectors, Sequences
... up performance tends to come from [Char] which the prelude has aliased as String. Char lists are convient, but tend to run on the order of 20 times slower than C strings, so feel free to use Data.Text or the very fast Data.ByteString. I'm sure there are other sequence oriented libraries I'm not t...
What is the purpose of std::make_pair vs the constructor of std::pair?
...
int main() {
MyClass<int> my_class(1);
}
then:
g++-8 -Wall -Wextra -Wpedantic -std=c++17 main.cpp
compiles happily, but:
g++-8 -Wall -Wextra -Wpedantic -std=c++14 main.cpp
fails with:
main.cpp: In function ‘int main()’:
main.cpp:13:13: error: missing template arguments before...
Avoid trailing zeroes in printf()
...01357
breaks it.
What you can do is to sprintf("%.20g") the number to a string buffer then manipulate the string to only have N characters past the decimal point.
Assuming your number is in the variable num, the following function will remove all but the first N decimals, then strip off the trai...
Generating a random password in php
...tor. Look elsewhere for generating a cryptographically secure pseudorandom string in PHP.
Try this (use strlen instead of count, because count on a string is always 1):
function randomPassword() {
$alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890';
$pass = array(...
Best way to reverse a string
I've just had to write a string reverse function in C# 2.0 (i.e. LINQ not available) and came up with this:
48 Answers
...
TLSF源码及算法介绍 - 开源 & Github - 清泛网 - 专注C/C++及内核技术
...*/
#ifndef USE_PRINTF
#define USE_PRINTF (1)
#endif
#include <string.h>
#ifndef TLSF_USE_LOCKS
#define TLSF_USE_LOCKS (0)
#endif
#ifndef TLSF_STATISTIC
#define TLSF_STATISTIC (0)
#endif
#ifndef USE_MMAP
#define USE_MMAP (0)
#endif
#ifndef USE_SBRK
#define USE_SBRK ...
Is there a print_r or var_dump equivalent in Ruby / Ruby on Rails?
...tributes_cache: {}
=> nil
>>
If you want to just preview some string contents, try using raise (for example in models, controllers or some other inaccessible place). You get the backtrace for free:)
>> raise Rails.root
RuntimeError: /home/marcin/work/github/project1
from (irb...
Repairing Postgresql after upgrading to OSX 10.7 Lion
...
Sorry, I forgot that I ran into that too. Added extra step to answer.
– Ben
Jul 28 '12 at 12:06
...
How can I check if a single character appears in a string?
...
You can use string.indexOf('a').
If the char a is present in string :
it returns the the index of the first occurrence of the character in
the character sequence represented by this object, or -1 if the
character does not occur...