iterate through two std::lists simultaneously

[Bengbers]

The following function constructs a std::vector<std::byte> object which is used for passing bind-arguments to a Query-object.
Line 4 specifies the variable to which values should be bound. Multiple items may be bound to a value, they are separated by a 0x01 byte. And each item consists of a value-string and a type-specifier (lines 6-8).
Line 10 removes the trailing 0x01.
The function does exactly what is expected.

void QueryObject::Bind(const std::string & name, const std::list<std::string> & valueList) {
	std::vector<std::byte> exec, result;
	std::string type { "" };
	pushByte(0x03, exec).addVoid(QueryID, exec).addVoid(name, exec);
	for (std::string val : valueList) {
		addVoid(val, exec);
		addVoid(type, exec);
		pushByte(0x01, exec);
	};
	exec.pop_back();
	handShake(exec, result);
	Response.setValues((std::string) __FUNCTION__, result);
};

This function uses a constant "" for the type, 'addVoid' replaces an empty string by a 0x00.

Is it possible to - after providing a third argument, typeList to the function - to change the loop in such a way that both lists are evaluated simultaneously? (Of course after checking that both lists have the same size).

[malibor]

It's possible but not with range for loop, instead you need the vintage version of the for loop :)

for (auto iter1 = list1.begin(), iter2 = list2.begin();
     (iter1 != list1.end()) && (iter2 != list2.end());
     ++iter1, ++iter2)
{
     // TODO: Insert code here to use iterators to both lists
}

btw: the "vintage" code is how B. Stroustrup calls code which does not use modern language features.

[mbozzi]

C++23, consider std::ranges::zip_view

for(auto [x, y]: std::views::zip(xs, ys))
{
  // ...
}

https://en.cppreference.com/w/cpp/ranges/zip_view

[seeplus]

re zip. For an article see https://www.cppstories.com/2023/view-zip/

[malibor]

mbozzi, Awesome solution, that's why I like this site because there's always something new to learn from you guys.

[Bengbers]

@mbozi
According to https://gcc.gnu.org/projects/cxx-status.html C++23 support in GCC is still experimental but this seems to be what I am looking for!

[seeplus]

For implementation, see https://en.cppreference.com/w/cpp/compiler_support

This indicates that GCC supports ranges::zip with v13