C ++从某个文件中搜索某行，然后在这些单词后面插入一个单词 [英] C++ searching a line from a file for certain words and then inserting a word after those words

问题描述

我非常新的C ++和ive一直在努力一段时间，试图找出如何做这个问题。基本上，我需要从一个文件中读取并查找一个文章的所有实例（a，A，an，aN，An，AN， tHe，thE，THe，tHE，ThE，THE），然后在文章后插入形容词。形容词的大写必须基于文章前面的词。例如，如果我发现一个鲨鱼，我需要使它一个快乐的鲨鱼。任何人都可以告诉我，最好的办法是什么？到目前为止，我已经废弃了很多想法，这是我现在，虽然我不认为我可以这样做：

Im very new to C++ and ive been struggling for quite a while trying to figure out how to do this problem. Basically, i need to read from a file and find all instances of an article ("a","A","an","aN","An","AN","the","The","tHe","thE","THe","tHE","ThE","THE")and then insert an adjective after that article. The adjective's capitalization must be based on the word originally in front of the article. For instance, if i found "a SHARK" i would need to make it "a HAPPY SHARK." Can anyone tell me what the best way to do this would be? So far I've scrapped a lot of ideas and this is what i have now, though i don't think i can do it this way:

#include <iostream>
#include <string>
#include <cctype>
#include <fstream>
#include <sstream>

using namespace std;

void
usage(char *progname, string msg){
    cerr << "Error: " << msg << endl;
    cerr << "Usage is: " << progname << " [filename]" << endl;
    cerr << " specifying filename reads from that file; no filename reads standard input" << endl;
}

int main(int argc, char *argv[])
{
    string adj;
    string file;
    string line;
    string articles[14] = {"a","A","an","aN","An","AN","the","The","tHe","thE","THe","tHE","ThE","THE"};
    ifstream rfile;
    cin >> adj;
    cin >> file;
    rfile.open(file.c_str());
    if(rfile.fail()){
        cerr << "Error while attempting to open the file." << endl;
        return 0;
    }
    while(rfile.good()){
        getline(rfile,line,'\n');
        istringstream iss(line);
        string word;
        while(iss >> word){
            for(int i = 0; i <= 14; i++){
                if(word == articles[i]){
                    cout << word + " " << endl;
                }else{
                    continue;
                }
            }
        }
        }
  }

推荐答案

到目前为止，很好，虽然如果你需要处理一行的结尾处的文章，那么你可能会有麻烦这行一行。

So far, pretty good, although if you need to handle an article at the end of a line, then you might be in trouble doing this line by line.

无论如何，忽略那个皱纹一秒钟，在你匹配一篇文章之后，首先你需要得到下一个字，你需要根据你的大小写。然后，您需要创建一个新的字符串版本的形容词，并且具有正确的大小写：

Anyway, ignoring that wrinkle for a second, after you've matched an article, then first you need to get the next word on which you need to base your capitalization. Then you need to create a new string version of your adjective that has the correct capitalization:

string adj_buf;  // big enough or dynamically allocate it based on adj

while(iss >> word){
    for(int i = 0; i <= 14; i++){
        if(word == articles[i]){
            cout << word + " ";
            iss >> word;  // TODO: check return value and handle no more words on this line
            adj_buf = adj;
            for (j = 0; j < word.size() && j < adj.size(); ++j)
                if (isupper(word[j]))
                    adj_buf[j] = toupper(adj[j]);
                else
                    adj_buf[j] = tolower(adj[j]);

            cout << adj_buf + " " + word;
            break;
        }
    }
}

忽略。你可能不想逐行，然后通过令牌令牌，因为处理这种特殊情况将是丑陋的在你的控制。相反，你可能想在一个循环中通过令牌来做它。

Circling back to the wrinkle we ignored. You probably don't want to do this line by line and then token by token because handling this special case will be ugly in your control. Instead, you probably want to do it token by token in a single loop.

因此，您需要编写一个帮助函数或类，对文件操作，并可以给你下一个令牌。 （可能在STL中已经有这样的类了，我不知道。）无论如何，使用你的I / O它可能看起来像：

So, you need to write a helper function or class that operates on the file and can give you the next token. (There probably is exactly such a class already in the STL, I'm not sure.) Anyway, using your I/O it might look something like:

struct FileTokenizer
{
    FileTokenizer(string fileName) : rfile(fileName) {}

    bool getNextToken(string &token)
    {
        while (!(iss >> token))
        {
            string line;

            if (!rfile.getline(rfile, line, '\n'))
                return false;

            iss.reset(line);  // TODO: I don't know the actual call to reset it; look it up
        }

        return true;
    }

private:
    ifstream      rfile;
    istringstream iss;
};

然后你的主循环如下：

FileTokenizer tokenizer(file);

while (tokenizer.getNextToken(word))
{
    for(int i = 0; i <= 14; i++){
        if(word == articles[i]){
            cout << word + " ";

            if (!tokenizer.getNextToken(word))
                break; 

            adj_buf = adj;
            for (j = 0; j < word.size() && j < adj.size(); ++j)
                if (isupper(word[j]))
                    adj_buf[j] = toupper(adj[j]);
                else
                    adj_buf[j] = tolower(adj[j]);

            cout << adj_buf + " " + word;
            break;
        }
    }
}

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