undefined behavior

The Ultimate Guide to C Language Arrays: From Two-Dimensional Matrices to Initialization Magic

by
The Ultimate Guide to C Language Arrays: From Two-Dimensional Matrices to Initialization Magic

Many students, when learning C language arrays, often settle for the simple use of one-dimensional arrays, but when faced with two-dimensional and multi-dimensional arrays, they feel overwhelmed, not to mention those “tricky operations” that make the compiler “guess” the size of the array. Recently, some attentive netizens have discovered some confusing points about array declarations … Read more

A Detailed Explanation of Sequence Points in C Language

by

A Detailed Explanation of Sequence Points in C Language Author: Luo Guangxuan In the C language, a sequence point is a “time point” in the execution process of a program, with the core rule being: all side effects of expressions (such as variable modifications) must be completely executed before the sequence point; new side effects … Read more

How Does the C Language Standard Describe and Require ‘const’?

by

The following content is from deepseek. In the C standard, ‘const’ is primarily a compile-time constraint and commitment that informs the compiler of the programmer’s intention not to modify this object. It does not directly specify the storage location of the object or its immutability at runtime. 1. Core Description of the C Standard (C11 … Read more

New Features in C++26 – Uninitialized Reads

by
New Features in C++26 - Uninitialized Reads

1. What are Uninitialized Reads Erroneous behaviour for uninitialized reads, or uninitialized reads. In traditional C++, UB (Undefined Behavior) is a very broad term; any behavior that does not fall under normal operations can be considered undefined. This overly broad definition often leads to a problem where, after an issue arises, it is difficult to … Read more

Avoiding Pitfalls in C Language: 2 Core Concepts to Help Beginners!

by
Avoiding Pitfalls in C Language: 2 Core Concepts to Help Beginners!

For those just starting with C language, do you often encounter these confusions: Your program compiles without errors, but suddenly crashes at runtime? You want to change the input every time the program runs, but can only modify the code and recompile? Today, we will break down two core concepts in C language that are … Read more

The 5 Most Dangerous Operations in C++: Lessons Learned from Years of Experience

by
The 5 Most Dangerous Operations in C++: Lessons Learned from Years of Experience

From WeChat Official Account: Program Cat Master This article summarizes what I believe to be the five most dangerous “self-destructive” operations in C++ development, each of which can cause your program to crash or exhibit hard-to-debug strange behaviors. These pitfalls are derived from painful lessons learned, and understanding and avoiding them will greatly enhance your … Read more

C++ Lambda Expression Closure Traps

by
C++ Lambda Expression Closure Traps

Lambda expressions are a powerful feature introduced in C++11 that can capture external variables to form a closure (Closure). However, if used carelessly, it is easy to fall into some hidden traps, leading to undefined behavior, dangling references, performance issues, or even crashes. Trap 1: Capturing local variables by reference, leading to dangling references This … Read more

In-Depth Understanding of C++ Lambda Expressions: Reference Capture Principles, Usage, and Potential Pitfalls

by
In-Depth Understanding of C++ Lambda Expressions: Reference Capture Principles, Usage, and Potential Pitfalls

Click the blue text to follow the author 1. Introduction C++ Lambda expressions allow for the inline definition of anonymous functions within code, resulting in a more compact and readable code structure. Lambda expressions are not just syntactic sugar; they also introduce the concept of capture lists, enabling Lambdas to access variables from their defining … Read more

Understanding C Language: Pre-increment/Decrement and Variable Evaluation

by
Understanding C Language: Pre-increment/Decrement and Variable Evaluation

Some textbooks describe pre-increment/decrement and post-increment/decrement as follows: Note: Within an expression, the increment/decrement operators may behave differently as part of the operation. If the increment/decrement operator is placed before the variable, the increment or decrement operation is completed before the variable participates in the expression; if the operator is placed after the variable, the … Read more