发现空格时，c ++将文件拆分为记录？

编程问答 2022-06-11

问题描述

我有一个像这样的文件

2.7388  0 2.4670
3.6384  1 24.5927
8.7844  0 10.6871
11.2892 0 2.6507
19.6054 1 16.8974
25.8811 0 8.0084

例如，我将采用第一行2.7388 0 2.4670 。我正在尝试完成以下操作

2.7388 = double x
0      = int y
2.4670 = double z

我的尝试

struct fileReader{
double x;
int y;
double z;
};

std::vector<fileReader> afileReader(std::string fileName) {

  std::vector<fileReader> readtheFile;
  std::ifstream List;
  std::string line;
  List.open(fileName);
 char delimiter = ' '; //delimiter added

  while (std::getline(List,line))
  {
    line.pop_back();
    std::string token;
    std::istringstream ss(line);
    fileReader afileReader;

    std::getline(ss,token,delimiter);
    afileReader.x = std::stod(token); //change from stoi to stod
 
    std::getline(ss,delimiter);
    afileReader.y = std::stoi(token);

    std::getline(ss,delimiter);
    afileReader.z = std::stod(token); //change from stoi to stod
    readtheFile.push_back(std::move(afileReader));
  }

for(fileReader x: readtheFile) {
      std::cout << x.x;
      std::cout << x.y;
      std::cout << x.z;
  }
  return readtheFile;
  passengerList.close();

}

从主行afileReader("file.txt") 开始运行时。我收到以下错误

terminate called after throwing an instance of 'std::invalid_argument'
  what():  stod //error changed
Aborted (core dumped)

我不确定为什么将stoi作为正确的转换方法将stoi转换为字符串（因为令牌是字符串）的错误

尽管我希望在打空格时拆分记录，但还是要回头再问。因此，请回到上一个示例2.7388 0 2.4670 ，当读取2.7388时将其分配给变量x，当读取0时将其分配给变量y，并且2.4670被分配给变量z

解决方法

（推荐）更直接的方法：

import { observer } from "mobx-react-lite";
import React,{ Fragment } from "react";
import {
  Route,RouteComponentProps,Switch,withRouter,} from "react-router-dom";
import { ToastContainer } from "react-toastify";
import { Container } from "semantic-ui-react";
import CheckinAuthorize from "../../features/checkin/CheckinAuthorize";
import CheckinDetails from "../../features/checkin/CheckinDetails";
import HomePage from "../../features/home/HomePage";
import NavBar from "../../features/nav/NavBar";
import NotFound from "./NotFound";

const App: React.FC<RouteComponentProps> = ({ location }) => {
  return (
    <Fragment>
      <Route exact path="/" component={HomePage} />
      <Route
        path={"/(.+)"}
        render={() => (
          <Fragment>
            <ToastContainer position='bottom-right'/>
            <NavBar />
            <Container style={{ marginTop: "7em" }}>
              <Switch>
                <Route exact path="/" component={HomePage} />
                <Route exact path="/checkin" component={CheckinAuthorize} />
                <Route path="/checkin/:id" component={CheckinDetails} />
                <Route component={NotFound} />
              </Switch>
            </Container>
          </Fragment>
        )}
      />
    </Fragment>
  );
};

export default withRouter(observer(App));

Sample Run

原始代码存在问题：

  1. import React from "react"; import { Menu,Container } from "semantic-ui-react"; import { observer } from "mobx-react-lite"; import { NavLink } from "react-router-dom"; const NavBar: React.FC = () => { return ( <div> <Menu fixed="top" inverted> <Container> <Menu.Item header as={NavLink} exact to="/"> <img src="/assets/logo.png" alt="logo" style={{ marginRight: "10px" }} /> Home </Menu.Item> </Container> </Menu> </div> ); }; export default observer(NavBar); 和#include <fstream> #include <iostream> #include <vector> struct Data { double x; int y; double z; }; std::vector<Data> fileReader(std::string fileName) { std::vector<Data> result; std::ifstream file(fileName); Data data; while (file >> data.x >> data.y >> data.z) result.push_back(data); for (auto &&i : result) std::cout << i.x << ' ' << i.y << ' ' << i.z << '\n'; return result; } int main() { fileReader("test.txt"); } 不是浮点数字。
  2. fileReader::x未被作为分隔符传递给对fileReader::z的调用。
  3. 正在读取的文件中的间距不一致。 （FIX）
  4. 出于某些奇怪的原因，您正在做' ';
  5. [某些警告的原因]您没有从std::getline（非无效函数）返回任何内容。

固定代码：

line.pop_back()
c++coredumpreadfile