Programming Leftovers

posted by Roy Schestowitz on Sep 27, 2022

• Commercial LTS Qt 6.2.6 Released

  We have released Qt 6.2.6 LTS for commercial license holders today. As a patch release, Qt 6.2.6 does not add any new functionality.

  You can add Qt 6.2.6 to the existing online installation by using the maintenance tool or do a clean installation by using the Qt Online Installer. Offline installers are available in the Qt Account download area.

• 165+ JavaScript terms you need to know | Opensource.com

  JavaScript is a rich language, with sometimes a seemingly overwhelming number of libraries and frameworks. With so many options available, it's sometimes useful to just look at the language itself and keep in mind its core components. This glossary covers the core JavaScript language, syntax, and functions.

• sscanf() Function in C

  In the various programming languages like C, we always encounter programs that contribute to taking the input from the user in the form of any value typed from the keyboard input, which involves the use of the scanf() method. But several other programs exist where we want to read the data formatted from the other string instead of keyboard input. For such types of reading formatted strings from one string to another, we use the sscanf() method. This function overwrites the value in one string with the other string, or when it extracts and breaks the one whole string into two different strings. Suppose we have a string “hi to the world”. We break and store this string into three other strings and store it in another variable; then, we may use the sscanf() method.

• Strstr Function in C

  The strstr() function is a built-in function used to process strings that are handled by library string.h. It is the library that provides us multiple functions to manipulate string. strstr() is used to find the specified main string’s first appearance of the matched substring by searching the source string. If the search is successful, it will return a pointer to the first substance of a substring in a string to be searched. In case it is appearing for more than once, it will pass the pointer to the first appearance of the substring. If the desired substring doesn’t appear, it will return null /0.

• Strtok Function in C

  “The strtok() function is a predefined C library function that enables us to break strings into multiple strings or zero, the most important point while splitting strings to keep in mind is that it can’t be empty or null.

  Two parameters are passed to the strtok() function that is responsible for tokenizing the string; the first parameter is the on that holds the string that is to be tokenized, while the second one is the delimiter that holds the keyword or character which will define the start and end of the string at which it is tokenized. The strtok() function ignores the delimiter part and simply displays the string that is right next to the delimiter.

  Whenever the strtok() function is called, the pointer to the next token, which is denoted by a null-terminated string, is returned. When it accounts for the end of the string where no token is discovered, it will return null.”

• Structures in C

  “In C Language, Structures are combined data type initialization that is used to group multiple variables in a single type; variables that are grouped must be related to each other. It allows those variables to be accessed by a single pointer. The main difference between a Structure and an Array is that an Array has only a single datatype, but on the other hand, a Structure can hold different datatypes. Hence, we can say that structure is a user-defined datatype that is used to store multiple variables with different datatypes in a single block to store a specific type or record.

  Let’s suppose we need to store a record of a person; that type of record will have attributes with different datatypes like Number, Name in Char, etc. For that purpose, we cannot use Array as it stores records with the same data type. The structure will come in handy in this case for us. It is a way to different group datatypes, and defining it means we are creating our new datatype.”

• Strncpy in C

  Strncpy is also known as String Copy Function. It is a crucial function that is offered by the C Language’s C String Library. Strncpy is responsible for copying a chunk of one string’s content into another.

• Static Variables in C

  “C is a very flexible language when it comes to allocating different variables in a function or outside the function. A static variable is one of those variables that are declared “statically” in a program. The starting value of the static variables is zero. Static variables continue to function while the program runs.”

• Switch Cases in C

  In the C programming language, sometimes we may encounter variables that have different operations for different values. Such a variable is known as the switch case variable. We use the switch case because it has the switch statements and it replaces the if else-if statements in the C. The switch case has one switch expression which is verified by comparing its value with the switch statements that keep on changing. If the value is matched, the statement, in that case, is printed. Otherwise, in the case where there is no match found, the default value is executed after checking the match in all switch cases.

  There are some restrictions on the use of these switch cases. First of all, the switch expression is required to have the data type char or integer. The value of each case should be used inside of the switch case statement and its data type must be an integer or const char (constant character).

• Typecasting in C

  “In typecasting, the compiler changes the datatype of our variables by itself based on how we want the program to run. C operations can only be performed with similar datatypes. If datatypes become different, then, in that case, typecasting will occur.

  In C Language, we define variables or constants with specific datatypes, if after the declaration of our variables, we are writing an expression or performing some operation, and we may get the output from it in a different type. So to maintain the type, we need typecasting for that purpose. Let’s suppose we are taking two integers and dividing them by each other; the result may be in a double datatype because of the points value. So to resolve the issue, we will use the concept of typecasting.

  There are two types of typecasting one is Implicit and the other one is Explicit.

  In Implicit Typecasting, the process is done by the compiler, and no information is lost. In Explicit Typecasting, we as a programmer will do the casting manually, and in doing so, we might lose the information.”