代码无法打开txt文件... [英] Code does not open txt file...

问题描述

我写了一段代码来打开一个txt文件并输入一些数据，但是记事本文件没有打开。这是代码...

I had written down a code to open a txt file and type in a few data, but the note pad file does not open. this is the code...

void cattywampus()
{
char str[30];
ifstream garbagein("notes.txt",ios::in);
ofstream fileout("vowel.txt",ios::out);
{   cout<<"Enter str";
cin>>str;
filein.getline(str,80,' ');
if(str[0]=='a'||str[0]=='e'||str[0]=='i'||str[0]=='o'||str[0]=='u')
cout<<str;
}
filein.close
fileout.close();
}

void main()
{
cattywampus();
}

What I have tried:

tried to save two notepad files as vowel and notes.txt

推荐答案

你怎么知道它没有打开文件？



但是在我们之前到那，为什么你这样做：

How do you know it doesn't open the file?

But before we get to that, why are you doing this:

cout<<"Enter str";
cin>>str;
filein.getline(str,80,' ');

由于最后一行会覆盖用户在第二行输入的内容吗？



另外，您创建输出流：

Since the last line will overwrite what the user enters in the second?

In addition, you create the output stream:

ofstream fileout("vowel.txt",ios::out);

但是你从来没有做任何事情！



从缩进代码开始：它使整个负载更具可读性。

But you never do anything with it!

Start off by indenting your code: it makes it a whole load more readable.

void cattywampus()
    {
    char str[30];
    ifstream garbagein("notes.txt",ios::in);
    ofstream fileout("vowel.txt",ios::out);
        {
        cout<<"Enter str";
        cin>>str;
        filein.getline(str,80,' ');
        if(str[0]=='a'||str[0]=='e'||str[0]=='i'||str[0]=='o'||str[0]=='u')
            {
            cout<<str;
            }
        }
    filein.close
    fileout.close();
    }

void main()
    {
    cattywampus();
    }

作为初学者，在之后总是使用花括号，如果， ，执行，，而，切换或 case - 以后修改代码会让生活变得更轻松！



回到你的问题：如何你知道吗？大概是因为你的输出文件没有包含任何数据。但是有两个原因可以解释为什么：

1）你覆盖了用户输入，所以如果你期望控制它，那就是原因的一部分！

2）你根本不写输出文件。



老实说，任何问题的第一个起点都不是问别人，它是通过寻找信息。这意味着在代码运行时查看代码，我们无法做到这一点。所以，这取决于你。

幸运的是，你有一个工具可以帮助你找到正在发生的事情：调试器。你如何使用它取决于你的编译器系统，但是一个快速的谷歌用于你的IDE名称和调试器应该给你你需要的信息。



放一个断点在函数的第一行，并通过调试器运行代码。然后查看您的代码，并查看您的数据并找出手动应该发生的事情。然后单步执行每一行检查您预期发生的情况正是如此。如果不是，那就是当你遇到问题时，你可以回溯（或者再次运行并仔细观察）以找出原因。


对不起，但我们不能为你做到这一点 - 时间让你学习一门新的（非常非常有用的）技能：调试！

And as a beginner, always use curly brackets after an if, for, do, while, switch, or case - it makes life a lot easier later when you modify the code!

And back to your problem: how do you know? Presumably because your output file doesn;t contain any data. But there are two reasons why that will be:
1) You overwrite the users input, so if that's what you expect to control it, that is part of why!
2) You don't write to the output file at all.

To be honest, the first place to start with any problem is not by asking others, it is by looking for information. And that means looking at your code while it is running, and we can't do that. So, it's going to be up to you.
Fortunately, you have a tool available to you which will help you find out what is going on: the debugger. How you use it depends on your compiler system, but a quick Google for the name of your IDE and "debugger" should give you the info you need.

Put a breakpoint on the first line in the function, and run your code through the debugger. Then look at your code, and at your data and work out what should happen manually. Then single step each line checking that what you expected to happen is exactly what did. When it isn't, that's when you have a problem, and you can back-track (or run it again and look more closely) to find out why.

Sorry, but we can't do that for you - time for you to learn a new (and very, very useful) skill: debugging!

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