


The difference between actual parameters and formal parameters in C language
The actual parameters are the actual values passed when the function is called, while the formal parameters are placeholder variables declared in the function definition to receive the actual parameter values. The actual parameters are determined when calling, and the formal parameters are determined when defining; the actual parameters can be changed, but the formal parameters can only be modified within the function body.
The difference between actual parameters and formal parameters in C language
In C language, the difference between actual parameters and formal parameters Parameters are two important concepts in function calls, and there are key differences between them.
Actual parameters
- Actual parameters are the values or variables that are actually passed to the function .
- They appear inside parentheses when calling a function.
- Actual parameters can be constants, variables, expressions or the function call itself.
Formal parameters
- Formal parameters are placeholder variables declared in function definition.
- They appear as type and name in the function header.
- When the function is called, the value of the actual parameter is passed to the corresponding formal parameter.
Difference
The main difference is:
- The actual parameter is the actual value passed when the function is called, while the formal parameter is Placeholder used when defining functions.
- The actual parameters are determined when the function is called, while the formal parameters are determined when the function is defined.
- The actual parameters can be changed, but the formal parameters can only be used and modified within the function body.
Example
Consider the following function definitions:
int sum(int a, int b) { return a + b; }
-
a
andb
It is a formal parameter and a placeholder variable.
When calling a function, the actual parameters are passed to the formal parameters:
int x = 5, y = 10; int result = sum(x, y);
-
x
andy
are actual parameters, use to actually pass to the function. -
a
andb
will receive the values ofx
andy
respectively.
The above is the detailed content of The difference between actual parameters and formal parameters in C language. For more information, please follow other related articles on the PHP Chinese website!

The choice of C XML framework should be based on project requirements. 1) TinyXML is suitable for resource-constrained environments, 2) pugixml is suitable for high-performance requirements, 3) Xerces-C supports complex XMLSchema verification, and performance, ease of use and licenses must be considered when choosing.

C# is suitable for projects that require development efficiency and type safety, while C is suitable for projects that require high performance and hardware control. 1) C# provides garbage collection and LINQ, suitable for enterprise applications and Windows development. 2)C is known for its high performance and underlying control, and is widely used in gaming and system programming.

C code optimization can be achieved through the following strategies: 1. Manually manage memory for optimization use; 2. Write code that complies with compiler optimization rules; 3. Select appropriate algorithms and data structures; 4. Use inline functions to reduce call overhead; 5. Apply template metaprogramming to optimize at compile time; 6. Avoid unnecessary copying, use moving semantics and reference parameters; 7. Use const correctly to help compiler optimization; 8. Select appropriate data structures, such as std::vector.

The volatile keyword in C is used to inform the compiler that the value of the variable may be changed outside of code control and therefore cannot be optimized. 1) It is often used to read variables that may be modified by hardware or interrupt service programs, such as sensor state. 2) Volatile cannot guarantee multi-thread safety, and should use mutex locks or atomic operations. 3) Using volatile may cause performance slight to decrease, but ensure program correctness.

Measuring thread performance in C can use the timing tools, performance analysis tools, and custom timers in the standard library. 1. Use the library to measure execution time. 2. Use gprof for performance analysis. The steps include adding the -pg option during compilation, running the program to generate a gmon.out file, and generating a performance report. 3. Use Valgrind's Callgrind module to perform more detailed analysis. The steps include running the program to generate the callgrind.out file and viewing the results using kcachegrind. 4. Custom timers can flexibly measure the execution time of a specific code segment. These methods help to fully understand thread performance and optimize code.

Using the chrono library in C can allow you to control time and time intervals more accurately. Let's explore the charm of this library. C's chrono library is part of the standard library, which provides a modern way to deal with time and time intervals. For programmers who have suffered from time.h and ctime, chrono is undoubtedly a boon. It not only improves the readability and maintainability of the code, but also provides higher accuracy and flexibility. Let's start with the basics. The chrono library mainly includes the following key components: std::chrono::system_clock: represents the system clock, used to obtain the current time. std::chron

C performs well in real-time operating system (RTOS) programming, providing efficient execution efficiency and precise time management. 1) C Meet the needs of RTOS through direct operation of hardware resources and efficient memory management. 2) Using object-oriented features, C can design a flexible task scheduling system. 3) C supports efficient interrupt processing, but dynamic memory allocation and exception processing must be avoided to ensure real-time. 4) Template programming and inline functions help in performance optimization. 5) In practical applications, C can be used to implement an efficient logging system.

ABI compatibility in C refers to whether binary code generated by different compilers or versions can be compatible without recompilation. 1. Function calling conventions, 2. Name modification, 3. Virtual function table layout, 4. Structure and class layout are the main aspects involved.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Atom editor mac version download
The most popular open source editor

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.
