Top new questions this week:

Is there any benefit to upgrading Java 7 compiled code to Java 8?

I have a old application written using Java 7. It runs fine in a Java 8 JRE. I do not plan on rewriting any of the code to make use of Java 8 features. Is there any technical benefit to upgrading the ...

java performance java-8

asked by g8torPaul 95 votes answered by Andrew 62 votes

Lambda capture and parameter with same name - who shadows the other? (clang vs gcc)

auto foo = "You're using g++!"; auto compiler_detector = [foo](auto foo) { std::puts(foo); }; compiler_detector("You're using clang++!"); clang++ 3.6.0 and newer print out "You're using clang++!" ...

c++ c++11 lambda language-lawyer shadowing

asked by Vittorio Romeo 92 votes answered by Columbo 47 votes

How to ensure that every method of a class calls some other method first?

I have : class Foo { public: void log() { } void a() { log(); } void b() { log(); } }; Is there a way that I can have each method of Foo, call ...

c++ c++11

asked by John 55 votes answered by Quentin 78 votes

Why is copying a shuffled list much slower?

Copying a shuffled range(10**6) list ten times takes me about 0.18 seconds: (these are five runs) 0.175597017661 0.173731403198 0.178601711594 0.180330912952 0.180811964451 Copying the unshuffled ...

python python-internals

asked by Stefan Pochmann 42 votes answered by MSeifert 54 votes

Differences when using ** in C

I started learning C recently, and I'm having a problem understanding pointer syntax, for example when I write the following line: int ** arr = NULL; How can I know if: arr is a pointer to a ...

c arrays pointers syntax

asked by TakaTiki 33 votes answered by StoryTeller 36 votes

Short form for Java If Else statement

I have a method which checks for nulls. Is there a way to reduce the number of lines in the method? Currently, the code looks "dirty": private int similarityCount (String one, String two) { if ...

java if-statement ternary-operator short

asked by userit1985 24 votes answered by Manh Le 50 votes

Why does C++ allow you to move classes containing objects with deleted move operations?

Why am I allowed to use std::move on a class which contains fields of a type with deleted move semantics (case 1), but am not allowed to use it on an instance of such a class (case 2)? I understand ...

c++ c++11 c++14 language-lawyer move-semantics

asked by mike 24 votes answered by songyuanyao 44 votes

Greatest hits from previous weeks:

WAMP error: Forbidden You don't have permission to access /phpmyadmin/ on this server

I am new to WAMP and I have just installed it today. The setup went well and localhost seems to work, but when I try to access phpMyAdmin I get this error: Forbidden You don't have permission ...

permissions wamp

asked by Nistor Alexandru 238 votes answered by Akhil Thayyil 334 votes

Why is it faster to process a sorted array than an unsorted array?

Here is a piece of C++ code that seems very peculiar. For some strange reason, sorting the data miraculously makes the code almost six times faster. #include <algorithm> #include <ctime> ...

java c++ performance optimization branch-prediction

asked by GManNickG 16914 votes answered by Mysticial 22986 votes

Can you answer these?

Resolving symbol in Windows debugger CDB

I am attempting to invoke a C++ function in a process that I attach to, via the Windows debugger CDB. The function is defined as: void LockerImpl<IsForMMAPV1>::dump() const { ... } The ...

c++ windows debugging windbg

asked by Jonathan Abrahams 7 votes

Validate one field based on another Field in redux Form

I am using redux-form, and my Component has several FieldArray. One of the FieldArray component generates table like shown in the screenshot. Here each row is a Field component including the checkbox. ...

reactjs redux-form

asked by Apan Madhesh 4 votes

Android Error retrieving parent for item: No resource found that matches the given name integrating ingo sdk

when I integrate an ingo SDK in my project I use to get the following error Error retrieving parent for item: No resource found that matches the given name Build tools of module(project) ...

android android-studio android-build android-build-type

asked by Bharat Kumar Emani 5 votes