how to get specific text from string?

[Reverseit]

I want to get player name from Chat log. Now I just need to find it from this line (param 1: `5<`2player`` entered, `w1`` others )

  std::string str="param 1: `5<`2PlayerNameIwant`` entered, `w1`` others here>``";


std::size_t pos = str.find("2");      // position of "2" in str
//but I don't want the stuff after "``" to be in my string. 
//not sure how to proceed, only done 2 days of c++.

[salem c]

Find the "2" then extract everything after it, so you get

str2 = "ThisAlwayschanges`` entered, `w1`` others here>``";

Find the "`", then extract everything before it, so you get

str3 = "ThisAlwayschanges";

https://www.cplusplus.com/reference/string/string/

[seeplus]

It's probably easier using a string stream. See http://www.cplusplus.com/reference/sstream/istringstream/

#include <sstream>
#include <string>
#include <iostream>

int main()
{
	const std::string str {"param 1: `5<`2PlayerNameIwant`` entered, `w1`` others here>``"};

	std::istringstream param(str);
	std::string name;

	std::getline(param, name, '2');		// Just to read and discard up to the 2. Could be .ignore() but getline() easier
	std::getline(param, name, '`');

	std::cout << name << '\n';
}

PlayerNameIwant

[Handy Andy]

Hello Reverseit,

You have a good start to find the "2". Now do the same to find the (`). Be careful with that (`) it is not the same as the ASCII ('). It did work in MSVS 2017 when I tested it, but for some it may not.

What you can do:

std::string str = "param 1: '5<'2PlayerNameIwant`' entered, 'w1'' others here>''";

std::size_t first = str.find("2");
std::size_t last = str.find("`");

std::cout << "\n " << str.substr(first + 1, last - first - 1) << '\n';

For line 6 take out the (+ 1) and (- 1) and see how that changes the output.

Andy

[seeplus]

@Andy. Not quite. Your L1 isn't the same as that of the OP. In the OP all are ` there are no '. You then need to start the find for ` starting from the position the 2 was found. Also, you need to check that 2 has been found. As C++17:

#include <string>
#include <iostream>

int main()
{
	const std::string str {"param 1: `5<`2PlayerNameIwant`` entered, `w1`` others here>``"};

	if (const auto first {str.find('2')}; first != std::string::npos) {
		const auto last {str.find('`', first)};

		std::cout << str.substr(first + 1, last != std::string::npos ? last - first - 1 : last) << '\n';
	}
}

[Handy Andy]

@seeplus,

I noticed that, but I have had trouble with the (`) in the past. Also had trouble with the double quote of the same type. After changing back to OP original string I found that it still worked, but by then he appeared to be finished.

Andy