Subtracting from strings?

How would I go about doing this? Here's what I have that works:

Code:

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string shipheight = "\n\n\n\n\n\n\n\n\n\n\n\n";
shipheight += "\n";

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This would come out with one more line. This doesn't work though:

Code:

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shipheight -= "\n";

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I want it to take away a line. How could I do that?

Well, assuming that you know for sure that the newline would be at the end:

Code:

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if (!shipheight.empty())
{
        shipheight.erase(shipheight.end() - 1);
}

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If you have to search, then:

Code:

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if (!shipheight.empty())
{
        std::string::size_type pos = shipheight.rfind('\n', shipheight.length() - 1);
        if (pos != std::string::npos)
        {
                shipheight.erase(shipheight.begin() + pos);
        }
}

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or use substr().

Code:

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if (!shipheight.empty())
{
        std::string::size_type pos = shipheight.rfind('\n', shipheight.length() - 1);
        if (pos != std::string::npos)
        {
                shipheight = shipheight.substr(0,pos);
        }
}

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Quote:

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Originally Posted by laserlight

Well, assuming that you know for sure that the newline would be at the end:

Code:

---

if (!shipheight.empty())
{
        shipheight.erase(shipheight.end() - 1);
}

---

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Thanks, that worked fine.

One more question: How can I make my program take input and make it do something while something else is happening?

I think what you want is Multithreading

Please start a new thread for a completely new topic.

You don't nessesarily need to use multithreading. If your compiler supports it, you might be able to use functions like kbhit() to determine whether there's a key in the input queue or not.

Quote:

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Originally Posted by dwks

You don't nessesarily need to use multithreading. If your compiler supports it, you might be able to use functions like kbhit() to determine whether there's a key in the input queue or not.

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Thanks, took me a while to figure it out, but that worked great.

I'll post a new thread for different problems from now on...