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Articles by George John
Page 50 of 79
How to generate a 24bit hash using Python?
A random 24 bit hash is just random 24 bits. You can generate these just using the random module. exampleimport random hash = random.getrandbits(24) print(hex(hash))OutputThis will give the output0x94fbee
Read MoreWhat are Aggregates and PODs in C++?
POD is an acronym in C++ that means plain old data. It is a class/struct that ONLY has member variables and no methods, constructors, destructors, virtual functions, etc. For example, Example#include using namespace std; // POD struct MyStruct { int key; string data; }; int main() { struct MyStruct s; s.key = 1; s.data = "hello"; return 0; }The struct MyStruct has no user defined ctor, dtor, etc and hence is a POD.An aggregate is an array or a class with no user-declared constructors, no private or protected non-static data members, no base ...
Read MoreDifference between const int*, const int * const, and int const * in C/C++?
The above symbols mean the following −int* - Pointer to int. This one is pretty obvious. int const * - Pointer to const int. int * const - Const pointer to int int const * const - Const pointer to const intAlso note that −const int * And int const * are the same. const int * const And int const * const are the same.If you ever face confusion in reading such symbols, remember the Spiral rule: Start from the name of the variable and move clockwise to the next pointer or type. Repeat until expression ends.
Read MoreHow can we drop UNIQUE constraint from a MySQL table?
For dropping UNIQUE constraint from a MySQL table, first of all, we must have to check the name of the index created by the UNIQUE constraint on the table. As we know that SHOW INDEX statement is used for this purpose. The ‘key_name’ in the result set of SHOW INDEX statement contains the name of the index. Now either with the help of DROP INDEX statement or ALTER TABLE statement, we can drop the UNIQUE constraint. The syntax for both the statements is as follows −SyntaxDROP INDEX index_name ON table_name; OR ALTER TABLE table_name DROP INDEX index_name;ExampleSuppose we have the ...
Read MoreListing modified, old and newly created files on Linux using C++
Here we will see how to list the modified files and old and newly created files on Linux platform using C++ program.The task is very simple. We can use the Linux shell command to get the files in desired order. The ls –l command is used to get all of the files in long listing format. Here we will add more options to sort them based on time. (Ascending and Descending). The –t command is used to sort based on time, and –r can be added to reverse the sequence.The command will be like below:ls –lt ls –ltrWe will use ...
Read MoreHow to perform SELECT using COUNT in MySQL?
To perform SELECT with COUNT, use aggregate function COUNT(). Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Name varchar(100), Subject varchar(100) ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Name, Subject) values('John', 'MySQL'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(Name, Subject) values('John', 'Java'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(Name, Subject) values('Carol', 'MongoDB'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(Name, Subject) values('Carol', ...
Read MoreWhat are all the common undefined behaviours that a C++ programmer should know about?
In C++, there are some undefined behaviors. These are identified by doing some tasks in C++. There are no such direct definitions. These few things should be known to all of the programmers, who want to use C++ for different purposes.Here we will see some C++ Codes. and try to guess the results. The codes will generate some runtime errors.The Divide By Zero error is undefined.Example Code#include using namespace std; int main() { int x = 10, y = 0; int z = x / y; cout
Read MoreHidden features of C++
Here we will see some good features and tricks of C++ programming language that can help us in different area. Like if we want to participate in some competitive programming events, then these tricks will help us to reduce the time for writing codes. Let us see some of these examples one by one.Checking whether a number is odd or even without using % operator. This trick is simple. We can perform bitwise AND operation with the number and 1. If the result is non-zero then this is odd, otherwise this is even. The logic is too simple. All odd ...
Read MoreHow to get the date between TODAY and TODAY-7"?
To get the date between dates, you need to use. Here, we are getting the dates between today and today-7 days −select *from yourTableName where DATE(yourColumnName) > (NOW() - INTERVAL 7 DAY);Note : Let’s say the current date is '2019-06-02’ Let us first create a table.mysql> create table DemoTable ( LoginDate date ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2018-03-21'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('2019-05-22'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('2019-05-27'); ...
Read MoreIs name a reserved word in MySQL?
No, name is not a reserved word in MySQL, you can use without backtick symbol. If you are working on a reserved word then use backtick symbol. Let us first create a table −mysql> create table name ( name varchar(10) ); Query OK, 0 rows affected (0.78 sec)Now you can insert some records in the table using insert command −mysql> insert into name values('John'); Query OK, 1 row affected (0.13 sec) mysql> insert into name values('Carol'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from name;Output+-------+ | name ...
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