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Why do we need virtual functions in C++?
I'm learning C++ and I'm just getting into virtual functions.
26 Answers
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Suppressing “is never used” and “is never assigned to” warnings in C#
...g restore 0169
To suppress warnings for "Field XYZ is never assigned to, and will always have its default value XX", you do this:
#pragma warning disable 0649
... field declaration
#pragma warning restore 0649
To find such warning numbers yourself (ie. how did I know to use 0169 and 0649), you ...
How do I install from a local cache with pip?
...irtualenv environments. Is there a way that I can download a package once and then have pip install from a local cache?
...
What is an undefined reference/unresolved external symbol error and how do I fix it?
...efined reference/unresolved external symbol errors? What are common causes and how to fix/prevent them?
34 Answers
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What is a “static” function in C?
...minology never uses the word "method"; that's Java terminology -- in C++ standard documents it is always called "member function" (see this answer or this glossary of C++ vs Java terms (e.g. C++ uses "data member" and Java uses "field", etc)).
– ShreevatsaR
Jan...
Difference between “on-heap” and “off-heap”
Ehcache talks about on-heap and off-heap memory. What is the difference? What JVM args are used to configure them?
6 Answ...
Passing command line arguments to R CMD BATCH
.... I am now at the point where I would like to pass an argument to the command, but am having some issues getting it working. If I do R CMD BATCH my_script.R blabla then blabla becomes the output file, rather than being interpreted as an argument available to the R script being executed.
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Why do x86-64 instructions on 32-bit registers zero the upper part of the full 64-bit register?
...ould almost never be used. (Making int 64-bit would waste cache footprint and memory bandwidth; x86-64 most efficiently supports 32 and 64-bit operand sizes)
The behaviour for 8 and 16-bit operand sizes is the strange one. The dependency madness is one of the reasons that 16-bit instructions are a...
mysqli_fetch_assoc() expects parameter / Call to a member function bind_param() errors. How to get t
... reason. Unfortunately, by default such errors are not transferred to PHP, and all you've got is a cryptic error message mentioned above. Hence it is very important to configure PHP and MySQLi to report MySQL errors to you. And once you get the error message, fixing it will be a piece of cake.
How...
How can I measure the similarity between two images? [closed]
...images with a text added vs. another without
mirrored images
The easiest and simplest algorithm I've seen for this is just to do the following steps to each image:
scale to something small, like 64x64 or 32x32, disregard aspect ratio, use a combining scaling algorithm instead of nearest pixel
sc...