Do I cast the result of malloc?

No; you don’t cast the result, since: It is unnecessary, as void * is automatically and safely promoted to any other pointer type in this case. It can hide an error, if you forgot to include <stdlib.h>. This can cause crashes (or, worse, notcause a crash until way later in

PHP: “Notice: Undefined variable” and “Notice: Undefined index”

Although PHP does not require variable declaration, it does recommend it in order to avoid some security vulnerabilities or bugs where one would forget to give a value to a variable that he will use later in the script. What PHP does in the case of undeclared variables is issue

Why shouldn’t I use mysql_* functions in PHP?

The MySQL extension: Is not under active development Is officially deprecated as of PHP 5.5 (released June 2013). Has been removed entirely as of PHP 7.0 (released December 2015) Lacks an OO interface Doesn’t support: Non-blocking, asynchronous queries Prepared statements or parameterized queries Stored procedures Multiple Statements Transactions The “new”

How do I compare strings in Java?

== tests for reference equality (whether they are the same object). .equals() tests for value equality (whether they are logically “equal”). Objects.equals() checks for nulls before calling .equals() so you don’t have to (available as of JDK7, also available in Guava). Consequently, if you want to test whether two strings

How do I return the response from an asynchronous call?

Explanation of the problem The A in Ajax stands for asynchronous. That means sending the request (or rather receiving the response) is taken out of the normal execution flow. In your example, $.ajax returns immediately and the next statement, return result;, is executed before the function you passed as successcallback

How can I prevent SQL-injection in PHP?

Question: How can I prevent SQL-injection in PHP? Answer: We can use following methods to prevent SQL-injection in PHP: Use prepared statements and parameterized queries These are SQL statements that are sent to and parsed by the database server separately from any parameters. This way it is impossible for an

What is a NullPointerException, and how do I fix it?

Question: What are Null Pointer Exceptions (java.lang.NullPointerException) ? Answer: When any one declare a reference variable (i.e. an object) it mean he  creating a pointer to an object. Consider the following code where you declare a variable of primitive type int: int x; x = 10; In this example the