Detailed explanation of C++ function library: system function extension and modular programming

C function library provides predefined functions, which can extend program functions and simplify programming. Types include standard libraries (STL), platform-specific libraries, and third-party libraries. Advantages include code reuse, consistency, feature extension, and modular programming. Usage steps: include header files, use namespaces, and call functions. Practical case: Storing and manipulating numbers using STL, showing examples using the vector library.

Detailed explanation of C function library: system function extension and modular programming

The function library is a set of pre-written functions. Can be used to extend the functionality of C programs, significantly simplifying programming tasks. This article takes an in-depth look at C libraries, including their types, benefits, and how to use them.

Function library type

• Standard function library (STL): Provides a wide range of data structures and algorithms.
• Platform-specific function library: Optimized for specific operating systems or platforms.
• Third-party function library: Contributed by external parties, providing a wide range of utilities such as database connections, graphics and networking.

Advantages of Function Library

• Code Reuse: No need to rewrite common functions, saving time and effort.
• Consistency: Ensures functionality is implemented in the same way in all programs.
• Function extension: Add new functions to the program without changing the underlying code.
• Modular programming: Code can be organized into manageable modules to improve maintainability.

Using the function library

Using the function library only requires a few simple steps:

1. Include the header file : Contains header files that provide function declarations, such as <vector></vector>.
2. Use namespace: Use the using directive to import the function library namespace, such as using namespace std;.
3. Call function: Call the function according to the syntax specified in the function declaration.

Practical case: Using STL to store and operate numbers

Sample code:

#include <vector>
#include <iostream>
using namespace std;

int main() {
  // 创建一个整数向量
  vector<int> numbers = {1, 2, 3, 4, 5};

  // 添加元素
  numbers.push_back(6);

  // 遍历并打印元素
  for (int num : numbers) {
    cout << num << endl;
  }

  // 获取向量大小
  cout << "Vector size: " << numbers.size() << endl;

  return 0;
}

Output :

1
2
3
4
5
6
Vector size: 6

This example shows how to use the vector function library to store and manipulate integers.

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