Expression statements

By Md Shoriful Islam

 Expression statements

Certain expressions (like x = 5) are useful by themselves (in this case, to assign the value 5 to the variable x). However, we mentioned above that expressions cannot be executed by themselves -- they must exist as part of a statement. So how can we use such expressions?

Fortunately, it’s easy to convert any expression into an equivalent statement (called an expression statement). An expression statement is a statement that consists of an expression followed by a semicolon. When the statement is executed, the expression will be evaluated.

Thus, we can take any expression (such as x = 5), and turn it into an expression statement (x = 5;) that will compile.

The result of an expression statement is discarded before the next statement is executed.

For advanced readers

An expression whose result is discarded is called a discarded-value expression). Expression statements are by far the most common type of discarded-value expressions.

Other discarded-value expressions include the left operand of the comma operator, and any expression that is cast to type void.

Useless expression statements

We can also make expression statements that compile but have no effect. For example, the expression statement (2 * 3;) is a expression statement whose expression evaluates to the result value of 6, which is then discarded. While syntactically valid, such expression statements are useless. Some compilers (such as gcc and Clang) will produce warnings if they can detect that an expression statement is useless.


Comments

Post a Comment

Popular posts from this blog

Whiteboarding Interviews

By Md Shoriful Islam
Image
 ⭕ Whiteboarding interviews are a common way of assessing the technical and non-technical skills of candidates for software development positions. They involve solving a coding problem or designing a system on a whiteboard, either in person or virtually, while explaining your approach and reasoning to the interviewer.  ⭕ Some of the benefits of whiteboarding interviews are that they can test your problem-solving ability, communication skills, and coding proficiency in a realistic scenario. They can also help you demonstrate your creativity, collaboration, and passion for the role. However, some of the drawbacks of whiteboarding interviews are that they can be stressful, artificial, and biased. They can also favor memorization over understanding and overlook other aspects of your skills and experience.  ⭕ If you want to ace a whiteboarding interview, you should practice beforehand, prepare for the interview setting, set objectives and expectations, create a good candidate ...
Read more

Version Control with Git: A Beginner’s Guide

By Md Shoriful Islam
Version Control with Git: A Beginner’s Guide If you are a developer, you probably know how important it is to keep track of your code changes and collaborate with other developers on a project. But how do you do that effectively and efficiently? The answer is version control. Version control is a system that records changes to a file or set of files over time so that you can recall specific versions later. It allows you to revert files back to a previous state, compare changes over time, see who last modified something, and more. Version control also enables you to work with other developers on the same code base without stepping on each other’s toes. One of the most popular version control systems in the world is Git. Git is a free and open source distributed version control system that is designed to handle everything from small to very large projects with speed and efficiency. Git has many features that make it superior to other version control systems, such as: Cheap local branchin...
Read more

Callback function in JavaScript

By Md Shoriful Islam
Image
Callback function in JavaScript What is a callback function in JavaScript? A callback function is a function that is passed as an argument to another function and is executed after the first function has completed its task. Callback functions are useful for handling asynchronous events, such as network requests, file operations, or timers. For example, you can use a callback function to display the result of a calculation after the calculation is done. Callback function in JavaScript Here is a simple example of a callback function in JavaScript: // Define a function that takes a callback as an argument function sayHello (callback) { // Do some task console .log ("Hello, world!"); // Invoke the callback function callback (); } // Define another function function sayGoodbye () { // Do some task console .log ("Goodbye, world!"); } // Call the first function and pass the second function as a callback sayHello (sayGoodbye); // The output will be: // Hello, wo...
Read more