在C++中检查stoi()函数中的int限制

Question

我得到了一个字符串y,其中我确保它只包含数字.在使用stoi函数将其存储在int变量中之前,如何检查它是否超出整数的边界？

string y = "2323298347293874928374927392374924"
int x = stoi(y); // The program gets aborted when I execute this as it exceeds the bounds
                 //   of int. How do I check the bounds before I store it?

Answer 1

你可以使用异常处理机制:

#include <stdexcept>

std::string y = "2323298347293874928374927392374924"
int x;

try {
  x = stoi(y);
}
catch(std::invalid_argument& e){
  // if no conversion could be performed
}
catch(std::out_of_range& e){
  // if the converted value would fall out of the range of the result type 
  // or if the underlying function (std::strtol or std::strtoull) sets errno 
  // to ERANGE.
}
catch(...) {
  // everything else
}

stoi函数的详细描述以及如何处理错误