Getting a string

Hi,

So, basically I want to extract a sequence of characters (which is located between two other sequences that I've given) from a string.

Code:

char* str="abcdefghi";
someFunction(str, "abc", "ghi"); 
//this is the function that would do what I want. It would return "def"- the sequence that is located between the given strings. It's not necessary for it to be one function, it could be any technique that accomplishes what I want.

Thank you.

Look at functions like "strstr".

Edit: I just realized that this is in the C++ section, in which case, perhaps you'd like to use the string class instead of char* for your string. In that case, functions find() and substr() are what you're looking for.

--
Mats

I too would recommend using std::string with find() and substr(). However, how would you handle say, "abcdefghighi"? If you have a greedy matching, then the string in between the two others would be "defghi". For such a case, you might use rfind() instead of find().

strstr() gives me the address of a substring in memory. How do I get the substring's location relative to the whole string?

EDIT

I'll try to use the C++ variant if I won't find a way to do it C-style.

Here is an example of a std::string function that finds a string between strings

Code:

#include <iostream>
#include <string>

std::string StringBetween(const std::string &findString, const std::string startString, const std::string endString)
{
	//Grab the length of the first string for moving the index
	size_t startLength = startString.length();
	size_t endLength = endString.length();

	//Sanity Check: Cannot find between empty strings
	if(0 == startLength || 0 == endLength){
		return "";
	}//if

	//Find the index of the first string
	size_t startIndex = findString.find(startString);

	//If we can't find that string return blank
	if(std::string::npos == startIndex){
		return "";
	}//if

	//Increment the start index to get the contents between
	startIndex = startIndex + startLength;

	//Find the index of the end string
	size_t endIndex = findString.find(endString, startIndex);

	//If we can't find it return blank
	if(std::string::npos == endIndex){
		return "";
	}//if

	//We found our string within our indexes return it back
	return findString.substr(startIndex, endIndex - startIndex);
}

int main()
{
	//The string to search between
	std::string findString = "abcdefghi";

	//The string that will contain the items between strings
	std::string subString = StringBetween(findString, "abc", "ghi");

	//Output the result
	std::cout<<subString;

	//"Wait" for input
	std::cin.get();
}