c++ - 输入c++的解析行

Question

我正在编写一个执行深度优先搜索的程序。是的，这是家庭作业，但我遇到问题的部分不是作业的学习点。我收到格式错误的输入，无法将输入分成有效变量并存储它们。当我说格式错误的数据时，我的意思是有效数据之间没有特定数量的空格，每行变量的数量不一致......试图找到一种更优雅的方式来获取我需要的数据而不是嵌套3个循环。任何帮助是极大的赞赏。我当前的代码:

int main()
{
    //read in first line (# of lines WITH data)
    cout << "enter the number of lines\n";
    cin >> lines;

    //if non integer entered it won't error now
    while(!cin)
    {
        cin.clear(); // clears the error flags
        cin.ignore(20, '\n'); //flush the buffer
        cout <<"\ndid not enter a valid integer, please try again\n\n";
        //reprompt for VALID input
        cout << "enter the number of lines\n";
        cin >> lines;
    }
    //lines should now have a valid int input value

    //eat blank line
    getline(cin,str);


    //read in (# of lines WITH data retrieved from first input)
    for(int i = 0; i < lines; i++)
    {
        getline(cin, str);// read first string
        //process str
        //while not end of line
        //{
    
        //breakup line into individual variables
        std::string delim = " "; //set space as a delimiter
        size_t pos = 0;
        string token;
        while ((pos = str.find(delim)) != std::string::npos)
        {
            token = str.substr(0,pos);
            //set token to variable that increases (array location?)

            //get char, loop to check if chare = " ", eat it if it is until its not

        }
        //}

        //place variables in array location
        //...
    }
    //eat blank line at end of data set
    getline(cin,str);

    //alphabetize array
    // ...

    return 0;
}

示例输入:

11

Harry       Kate(18)       Fred(5)        Carol(6)
Alice      James(25)       Daisy(21)      Kate(10)
Carol     Fred(2)         Harry(6)       Daisy(12)
Ivy        James(16)       Bob(24)
Daisy       Carol(12)     Alice(21)     Elvis(28)
Elvis        James(18)       Daisy(28)      Fred(29)
Kate       Alice(10)      Fred(14)       Harry(18)    Gerald(20)
Fred        Kate(14)       Carol(2)     Harry(5)     Elvis(29)
Gerald      Kate(20)       Bob(17)    James(10)
James       Gerald(10)      Elvis(18)       Alice(25)   Ivy(16)
Bob     Ivy(24)        Gerald(17)

Answer 1

您可以使用 std::istringstream 和 std::istream_iterator 标记每一行。下面给出了示例代码。

#include <iostream>
#include <iterator>
#include <vector>
#include <string>
#include <sstream>

template <typename T>
std::vector<T> parse_line(const std::string& s) {
  std::vector<T> result;
  std::istringstream iss(s);
  std::copy(std::istream_iterator<T>(iss), std::istream_iterator<T>(),
            std::back_inserter(result));
  return result;
}

int main() {
  std::string s{"Harry       Kate(18)       Fred(5)        Carol(6)"};
  auto r = parse_line<std::string>(s);
  for (auto const& e : r) std::cout << e << std::endl;
  return 0;
}