c++ - c++ Parsing prices of a text file

Question

I need to parse the following file so it takes the item as a string then skip the # sign and then take the price as a float. text file:

hammer#9.95
saw#20.15
shovel#35.40

how would I go about doing this?

Answer 1

将文件逐行读入字符串。查找#第二部分并将其解析为浮点数。

std::ifstream file("input.txt");

for (std::string line; std::getline(file, line); )
{
    auto sharp = line.find('#'); // std::size_t sharp = ... 

    if (sharp != std::string::npos)
    {
        std::string name(line, 0, sharp);

        line.erase(0, sharp+1);

        float price = std::stof(line);

        std::cout << name << " " << price << "\n";
    }
}

注意：我没有做一些错误检查，作为练习自己做。你也应该知道std::string,std::ifstream和.std::getlinestd::stof

Answer 2

如果你有 std::string 呈现格式，你可以使用这样的东西：

std::string test {"test#5.23"};
std::cout << std::stof(std::string{test.begin() + test.rfind('#') + 1, test.end()});

注意 std::stof 是 C++11 函数