How to catch specific types of exceptions in C++ function exception handling?

Methods to catch specific types of exceptions in C: use try-catch blocks. Specify the type of exception to be caught in the catch clause, such as catch (const std::runtime_error& e). In a practical case, the read_file() function handles the case where the file does not exist by throwing std::runtime_error, and uses a try-catch block to catch this exception and print the error message.

Catch specific types of exceptions in C function exception handling

In C, use try-catch When a block handles exceptions thrown in a function, you can use the catch clause to catch specific types of exceptions. For example, to catch exceptions of type std::runtime_error, you can use the following syntax:

try {
  // 函数代码
} catch (const std::runtime_error& e) {
  // 处理 std::runtime_error 异常
}

Actual case:

Assume there is a read_file() Function, which is responsible for reading data from the file. If the file does not exist, the function throws a std::runtime_error exception. We can use a try-catch block to handle this exception:

#include <iostream>
#include <fstream>

void read_file(const std::string& filename) {
  std::ifstream file(filename);
  if (!file.is_open()) {
    throw std::runtime_error("File not found");
  }
  
  // 读取文件内容
}

int main() {
  try {
    read_file("myfile.txt");
  } catch (const std::runtime_error& e) {
    std::cerr << "Error: " << e.what() << std::endl;
  }
  return 0;
}

Running this program, if the file "myfile.txt" does not exist, the following error message will be printed:

Error: File not found

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