如何逐行检查txt文件中的单词，何时找到打印整行？ [英] How to check for a word in a txt file line by line and when found print the whole line?

问题描述

逐行检查文本文件中的单词，找到时打印整行包含单词.Pleas尽快帮助。



我尝试过：



这里是代码： -

这里cw是一个指针存储在其中的行，w是要搜索的单词，gw也是用于存储从每行获得的单词的指针。



while（！o。 eof（））

{

o.getline（cw，'\ n'）;

for（i = 0; cw [ i]！='\''; i ++）

{

gw [i] = cw [i];

}

// if（cw [i] == w [i]）

if（gw == w）

cout<< cw;

如果（o.eof（））休息;

}

o.close（）;

To check for a word in a text file line by line and when found print the whole line which is containing the word .Pleas help as fast as possible.

What I have tried:

here is the code:-
Here cw is a pointer having the line stored in it,w is the word to be searched for, gw is also a pointer used to store the word obtained from each line.

while (!o.eof())
{
o.getline(cw,'\n');
for(i=0;cw[i]!='\0';i++)
{
gw[i]=cw[i];
}
// if(cw[i]==w[i])
if(gw==w)
cout<<cw;
if(o.eof())break;
}
o.close();

推荐答案

#include <iostream>
#include <fstream>
using namespace std;

int main()
{
  ifstream ifs("in.txt");

  string word = "foo";
  string line;

  while( getline(ifs, line ))
  {
    size_t pos = line.find(word);
    if ( pos != string::npos)
      cout << line << endl;
  }
}

[update]

如果你不想要foofighters ，那就是你需要在单词边界之间搜索你的单词（如你自己和 KarstenK 所暗示的那样），那么你可以使用常规表达式：

[update]
If you don't want foofighters, that is if you need to search your word between word-boundaries (as hinted by yourself and KarstenK) then you might use a regular expression:

#include <iostream>
#include <fstream>
#include <regex>
using namespace std;

int main ()
{
  ifstream ifs("in.txt");

  string word = "foo";

  std::regex e{"\\b" + word + "\\b"};

  string line;

  while( getline(ifs, line ))
  {
    if ( regex_search( line, e) )
      cout << line << endl;
  }
}

[/ update]

我用C ++编写了一个小函数来解决你的问题。请检查它是否有效按下那个小绿色按钮接受解决方案。

Hi,

I wrote a little function in C++ to solve your problem. Please check it out and if it worked press that little green button to accept the solution.

#include <iostream>
#include <fstream>
#include <string>

int main()
{
	std::cout << "Write the path of the file\n";
	std::string path;
	std::cin >> path;

	std::ifstream file(path.c_str());

	if (file.is_open())
	{
		std::cout << "File '" << path << "' opened.\n";

		std::cout << "Write the word you're searching for\n";
		std::string word;
		std::cin >> word;
		std::string line;

		std::string candidate;

		while (!file.eof()) // for each candidate word read from the file 
		{
			std::getline(file, line);
			std::size_t found = line.find(word);
			if (found != std::string::npos)
				std::cout << "The word '" << word << "' has been found in line " << line;
		}
		file.close();
	}

	else
	{
		std::cerr << "Error! File not found!\n";
		return 1;
	}
}

如果这不能解决您的问题，请发表评论，我会帮助您通过改进我的解决方案，直到你的问题得到解决。



干杯，

AH

If this did not solve your problem then please leave a comment and I will assist you by improving my solution until your problem gets solved.

Cheers,
AH

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