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Programming is thinking, not typing |
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The frequently asked problem on interviews.
You have a log of some user activities represented as a table. Every activity record has at least users ID and activity date/time values.
The session is a sequence of activities having less than N minutes between two log records. When the elapsed …
The opaque pointer (pimpl) idiom has been inherited from C language where it is used to encapsulate implementation details. However, both old-school and "modern" C++ dispense you from writing some ugly code, and allow to use interfaces with object factories.
The example of implementation with both pimpl and interface approach …
How to extract all combinations (unordered subsets) from a given set in C++?
Let us estimate the count before. Suppose N is the size of a given set, and K is the number of elements in the subset. The count of all combinations (unordered subsets) of size K is
C …
Suppose a string of ordered cyphers 123456789. You can insert signs "+" and "-" between any cyphers to make a correct arithmetical expression. The problem is to find all expressions which sum is 100.
This problem may be interesting for dynamic script languages having the function of a string expression evaluation.
E …
Unlike Java or C#, the C++ world does not have a unified coding standard. The naming convention is still the choice of programmer teams or enterprises.
However, there are several standards widely used in the software industry.
Do not use static_cast when you cast from a basic class to a derived one. This may lead to undefined behavior. To handle the polymorphism, a virtual inheritance or a multiple inheritance case always use dynamic_cast instead.
The following short example shows the undefined behavior cases. This works with GCC …
Here we go. "The sleep of reason produces monsters"
Previously, comparing C++Builder classic and Clang compilers I regreted than CodeGuard tool doesn't work with Clang. Fortunately, there are other tools which can help you to profile program code and detect memory leaks. The Dataleaker is the one of these tools.
The installation requires local administrator rights …
How to kill all database connections before dropping it?
USE master;
GO
DECLARE @sql nvarchar(max);
WHILE 1=1 BEGIN
SELECT TOP 1 @sql = N'KILL ' + convert(nvarchar(10), spid)
FROM sysprocesses WHERE dbid = DB_ID('my_database');
IF @@rowcount = 0 BREAK;
EXEC sp_executesql @sql;
END;
DROP DATABASE IF EXISTS my_database;
Priority to keep in mind:
#include <stdio.h>
int main()
{
int arr[] = {10, 20};
int *p1 = arr;
int *p2 = arr;
int *p3 = arr;
printf("arr[0] = %d, arr[1] = %d\n", arr[0], arr[1]);
printf("arr[0] = %d, arr[1 …