How does the C++ function library handle exceptions?

C function library exception handling is implemented through the try-catch statement, which can capture exception types and handle them. Common exception types include logic errors, runtime errors, memory allocation failures, type conversion failures, and index out-of-range. The actual case demonstrates exception handling when reading files, which can output error messages or take corresponding measures.

Exception handling in C function library

In large-scale software development, the exception handling mechanism is crucial, it can effectively handle the process of running the program various unexpected situations. This article will introduce how to use the C function library to establish an efficient exception handling mechanism, and provide practical cases for reference.

Exception handling mechanism

The C function library implements the exception handling mechanism through the try-catch statement:

try {
  // 可能引发异常的代码
} catch (异常类型1& e) {
  // 捕获异常类型1并进行处理
} catch (异常类型2& e) {
  // 捕获异常类型2并进行处理
}
...

Common exception types

C standard library defines many exception types, the most common of which are:

• std::logic_error: Logic errors, such as parameter errors, invalid status, etc.
• std::runtime_error: Runtime errors, such as memory allocation failure, file access failure, etc.
• std::bad_alloc: Memory allocation failure
• std::bad_cast: Type conversion failed
• std::out_of_range: Index or iterator out of range

Actual combat Case

Scenario:Open a file and read its contents

Code:

#include <iostream>
#include <fstream>

using namespace std;

int main() {
  string filename;
  cout << "请输入文件名：";
  cin >> filename;

  try {
    ifstream file(filename);

    if (!file) {
      throw runtime_error("文件打开失败！");
    }

    // 读取文件内容
    string line;
    while (getline(file, line)) {
      cout << line << endl;
    }
  } catch (runtime_error& e) {
    cout << "发生了运行时错误：" << e.what() << endl;
  }

  return 0;
}

Execution effect:

If the file is opened successfully, the program will print out the contents of the file. Otherwise, the program will output "A runtime error occurred:" and display the specific error message.

Summary

Using the exception handling mechanism of the C function library can effectively deal with unexpected situations during program running. This article introduces the basic principles of exception handling, common exception types, and provides practical cases for developers' reference.

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