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Programming Articles
Page 2481 of 2547
How to get memory usage at runtime using C++?
We can get the memory usage like virtual memory usage or resident set size etc. at run time. To get them we can use some system libraries. This process depends on operating systems. For this example, we are using Linux operating system.So here we will see how to get the memory usage statistics under Linux environment using C++. We can get all of the details from “/proc/self/stat” folder. Here we are taking the virtual memory status, and the resident set size.Example#include #include #include #include #include using namespace std; void mem_usage(double& vm_usage, double& resident_set) { ...
Read MoreHow to position component at the top of the grid cell with GridBagLayout in Java?
To position components at the top fo the grid cell, set the GridBagConstraints. Let’s say we have a panel and within that two CheckBox components −JPanel panel1 = new JPanel(new GridBagLayout()); JCheckBox checkBox1 = new JCheckBox("Undergraduate"); JCheckBox checkBox2 = new JCheckBox("Graduate");Position the components now −panel1.add(checkBox1, new GridBagConstraints(0, 0, 1, 1, 1.0, 1.0, GridBagConstraints.NORTH, GridBagConstraints.NORTH, new Insets(0, 0, 0, 0), 0, 0)); panel1.add(checkBox2, new GridBagConstraints(1, 0, 1, 1, 2.0, 0.0, GridBagConstraints.NORTH, GridBagConstraints.NORTH, new Insets(0, 0, 0, 0), 0, 0));The following is an example to position component at the top of the grid cell with GridBagLayout −Examplepackage my; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.Insets; ...
Read MoreIs it mandatory to register the driver while working with JDBC?
Initially, till Java6 it is needed to register the driver using Class.forname() or the registerDriver() method before establishing connection with the database.But, since Java 1.6, JDBC 4.0 API, there is no need to register the driver explicitly, You Just need to set the Class path for the JDBC 4.X driver, Java automatically detects the Driver class and loads it.ExampleIn the following JDBC program we are trying connect with MySQL database first of all include the dependency for the MySQL driver in the pom.xml of your project. mysql mysql-connector-java 8.0.16 Then, without registering the MySQL driver class com.mysql.jdbc.Driver ...
Read MoreHow to insert a DATALINK object into a table using JDBC?
A DATALINK object represents an URL value which refers to an external resource (outside the current database/data source), which can be a file, directory etc.You can store a DATALINK into an SQL table using the setURL() method of the PreparedStatement interface. This method accepts an integer value representing an index of the bind variable, an URL object and, inserts the given URL object in the column represented by the bind variable in the specified index.ExampleLet us create a table with name tutorials_data in MySQL database using CREATE statement as shown below −CREATE TABLE tutorials_data ( tutorial_id INT PRIMARY KEY ...
Read MoreHandling large numbers in C++?
In C++, we can use large numbers by using the boost library. This C++ boost library is widely used library. This is used for different sections. It has large domain of applications. For example, using boost, we can use large number like 264 in C++.Here we will see some examples of boost library. We can use big integer datatype. We can use different datatypes like int128_t, int256_t, int1024_t etc. By using this we can get precision up to 1024 easily.At first we are multiplying two huge number using boost library.Example#include #include using namespace boost::multiprecision; using namespace std; int128_t large_product(long ...
Read MoreHow to set Palette Layer for JDesktopPane in Java?
At first, create a JDesktopPane −JDesktopPane desktopPane = new JDesktopPane();Now, create an Internal Frame −JInternalFrame intFrame = new JInternalFrame("Our Frame", true, true, true, true); intFrame.setBounds(50, 90, 200, 250);Set Pallette layer for JDesktopPane and add the Internal Frame to JDesktopPane −intFrame.putClientProperty("JInternalFrame.isPalette", Boolean.TRUE); desktopPane.add(intFrame, JDesktopPane.PALETTE_LAYER);The following is an example to set palette layer for JDesktopPane −package my; import java.awt.BorderLayout; import javax.swing.JButton; import javax.swing.JDesktopPane; import javax.swing.JFrame; import javax.swing.JInternalFrame; import javax.swing.JLabel; public class SwingDemo { public static void main(final String[] args) { JFrame frame = new JFrame("Demo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JDesktopPane desktopPane = new JDesktopPane(); ...
Read MoreHow to retrieve a DATALINK object from a table using JDBC?
A DATALINK object represents an URL value which refers to an external resource (outside the current database/data source), which can be a file, directory etc..You can retrieve a DATALINK object an SQL table using the getURL() method of the PreparedStatement interface. This method accepts an integer value representing an index of the column in the ResultSet and returns the URL object in the specified index.ExampleLet us create a table with name tutorials_data in MySQL database using CREATE statement as shown below −CREATE TABLE tutorials_data ( tutorial_id INT PRIMARY KEY AUTO_INCREMENT, tutorial_title VARCHAR(100), tutorial_author VARCHAR(40), submission_date date, ...
Read MoreHow to get time in milliseconds using C++ on Linux?
Here we will see how to get time (the elapsed time for the program or any other kind of time).Here we are using linux library for C++. There is a structure called timeval. This timeval stores the time in seconds, milliseconds. We can create two time for start and end, then find the difference from them.Example#include #include #include using namespace std; main() { struct timeval start_time, end_time; long milli_time, seconds, useconds; gettimeofday(&start_time, NULL); cout > ch; gettimeofday(&end_time, NULL); seconds = end_time.tv_sec - start_time.tv_sec; //seconds useconds = end_time.tv_usec - start_time.tv_usec; //milliseconds ...
Read MoreHow to use GridBagConstraints to layout two components in the same line with Java
To align two components in the same line, you need to set the contrainsts of the GridBagConstraints properly. Let’s say we have two components in panel1. Set the contraints using Insets as well −panel1.add(checkBox1, new GridBagConstraints(0, 0, 1, 1, 0.0, 0.0, GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL, new Insets(0, 0, 0, 0), 0, 0)); panel1.add(checkBox2, new GridBagConstraints(1, 0, 1, 1, 2.0, 0.0, GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL, new Insets(0, 0, 0, 0), 0, 0));The following is an example to set two components in the same line −Examplepackage my; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.Insets; import javax.swing.JCheckBox; import javax.swing.JFrame; import javax.swing.JPanel; public class SwingDemo { ...
Read MoreWrite a program to get the list of all the supported datatypes in JDBC?
The class named Types of the java.sql package contains the constants that represents the SQL datatypes. All these datatypes are represented by unique integer values.Retrieving the integer values from the Types classTo print all the class names and values of the constants in java.sql.Types class −Retrieve all the fields in Types class − The getFields() method of the class Class returns an array which holds all the fileds (public) of the class/interface represented by the current Class object.Using this method retrieve the array of fileds of the Types class as shown below −Field[] fields = java.sql.Types.class.getFields();Retrieve the name and value ...
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