检测新行c ++ fstream [英] Detect new line c++ fstream

问题描述

如何通过使用fstream将类似的内容复制到另一个.txt中.txt。
问题是，当在文件中有新行。如何检测，而使用ifstream？

用户输入苹果

例如：
note.txt =>
昨天我买了一个苹果。
苹果口味好吃。
$ b $ note_new.txt =>
我昨天买了一个。
味道鲜美。

由此产生的钞票假设在上面，而是：
note_new.txt =>
我买了一个昨天。味道鲜美。

如何检查源文件中是否有新行，还会在新文件中创建新行。 b

以下是我目前的代码：

  #include< iostream> 
 #include< fstream> 
 #include< string> 
 
使用namespace std; 
 
 int main（）{
 ifstream inFile（note.txt）; 
字符串字; 
 ofstream outFile（note_new.txt）; 
 
 while（inFile>> word）{
 outfile<<字<< ; 
} 
} 
  

你们能帮助我吗？其实我也检查检索的单词是什么时候与用户指定的相同，然后我不会在新文件中写入该单词。所以一般来说，它会删除与用户指定的单词相同的单词。 解决方案

逐行方法

如果您仍想逐行执行，您可以使用 std :: getline（） ：

  #include< iostream> 
 #include< fstream> 
 #include< string> 
 
使用namespace std; 
 
 int main（）{
 ifstream inFile（note.txt）; 
字符串行; 
 // ^^^^ 
 ofstream outFile（note_new.txt）; 
 
 while（getline（inFile，line））{
 // ^^^^^^^^^^^^^^^^^^^^^ 
 outfile <<行<< ENDL; 
 
 
 
 
 $ b $ p 
 $ b $ p $ 
 
 $ h 
 $ b 
更容易的方法
 
 
 
如果你只是想重写另一个文件，使用  rdbuf  ：
 
 
  #include< fstream> 
 
使用namespace std; 
 
 int main（）{
 ifstream inFile（note.txt）; 
 ofstream outFile（note_new.txt）; 
 
 outFile<< inFile.rdbuf（）; 
 // ^^^^^^^^^^^^^^^^^^^^^^^^^^ 
} 
  
 
 
 
 
 
 
 编辑：允许删除您不想要的字词在新文件中：
 
 
 
我们使用  std :: stringstream  ：
 
 
  #include<的iostream> 
 #include< fstream> 
 #include< stringstream> 
 #include< string> 
 
使用namespace std; 
 
 int main（）{
 ifstream inFile（note.txt）; 
字符串行; 
 string wordEntered（apple）; //从命令行获取
 ofstream outFile（note_new.txt）; 
 
 while（getline（inFile，line））{
 
 stringstream ls（line）; 
字符串字; 
 
 while（ls>> word）
 {
 if（word！= wordEntered）
 {
 outFile<字; 
} 
} 
 outFile<< ENDL; 
} 
} 
  
 
How do I read a .txt copy the content to another .txt by using fstream to a similar content.
The problem is, when in the file there is new line. How do I detect that while using ifstream?

user enter "apple"

Eg:
note.txt =>
I bought an apple yesterday.
The apple tastes delicious.

note_new.txt => 
I bought an yesterday. 
tastes delicious.

the resulting note suppose to be above, but instead:
note_new.txt => 
I bought an yesterday. tastes delicious.

How do I check if there is a new line in the source file, it also will create new line in new file.

Here is my current code:
#include <iostream>
#include <fstream>
#include <string> 

using namespace std;

int main() {
    ifstream inFile ("note.txt");
    string word;
    ofstream outFile("note_new.txt");

    while(inFile >> word) {
        outfile << word << " ";
    }
}
can you all help me? actually I also check when the word retrieved is the same as what user specified, then I won't write that word in the new file. So it general, it will delete words which are the same as the one specified by user.
解决方案
Line-by-line method

If you still want to do it line-by-line, you can use std::getline() :
#include <iostream>
#include <fstream>
#include <string> 

using namespace std;

int main() {
    ifstream inFile ("note.txt");
    string line;
    //     ^^^^
    ofstream outFile("note_new.txt");

    while( getline(inFile, line) ) {
    //     ^^^^^^^^^^^^^^^^^^^^^
        outfile << line << endl;
    }
}
It gets a line from the stream and you just to rewrite it wherever you want.



Easier method

If you just want to rewrite one file inside the other one, use rdbuf :
#include <fstream>

using namespace std;

int main() {
    ifstream inFile ("note.txt");
    ofstream outFile("note_new.txt");

    outFile << inFile.rdbuf();
//  ^^^^^^^^^^^^^^^^^^^^^^^^^^
}




EDIT : It will permit to remove the words you don't want to be in the new file :

We use std::stringstream :
#include <iostream>
#include <fstream>
#include <stringstream>
#include <string> 

using namespace std;

int main() {
    ifstream inFile ("note.txt");
    string line;
    string wordEntered("apple"); // Get it from the command line
    ofstream outFile("note_new.txt");

    while( getline(inFile, line) ) {

        stringstream ls( line );
        string word;

        while(ls >> word)
        {
            if (word != wordEntered)
            {
                 outFile << word;
            }
        }
        outFile << endl;
    }
}


                        
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