Adding an integer to a string.

Hi, if I have a basic function, lets say sampleStr which contains some string. I have another, integer, function and would like to add the result of that function, in integer format to the end of the string, then how can I do it.

I have tried what I think i should do, but that only returns the relative character (ie I want 65 put in, but 'A' is put in instead.

Thanks in advance,
mintsmike

Look up the stringstream (ostringstream in particular), within the standard <sstream> header.

Alternatively, if you want to use the "C way", look up sprintf() in <stdio.h> or <cstdio>.

Yes, you need something that translates a number into a string of characters that represent that number. Stringstreams will work.

Code:

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#include <cstdlib> //rand()
#include <string>
#include <sstream>
#include <iostream>

int main()
{
  std::string initial("This number was generated randomly: ");
  std::ostringstream oss;
  oss << std::rand();
  initial += oss.str();
  std::cout << initial << std::endl;
}

---

EDIT: of course, this program prints number that's random until you look at it. Then it won't seem so random when the you it again.

It's too bad that operator << always returns an ostream&. If somehow it remembered what type was involved we could:

Code:

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cout << (ostringstream() << number << date << string << 'a').str() << endl;

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Maybe in another lifetime.

Quote:

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cout << (ostringstream() << number << date << string << 'a').str() << endl;

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What?

Not much different from:

Code:

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std::ostringstream ostrm;
ostrm << number << date << string << 'a';
std::cout << ostrm.str().c_str() << std::endl;

---

Two lines different.

Quote:

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Originally Posted by CodeMonkey

Two lines different.

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In labouring to be concise, your code eventually becomes obscure or unmaintainable.

Code:

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cout << (ostringstream() << number << date << string << 'a').str() << endl;

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O_o

Code:

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cout << number << date << string << 'a' << endl;

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Soma

Well there's the coup de grâce.

Quote:

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Originally Posted by grumpy

In labouring to be concise, your code eventually becomes obscure or unmaintainable.

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But you might want something that turns an integer into a string with only one line, ala boost::lexical_cast. That's not very obscure.