I have a Struct containing about a 300 variables
and i have a string containing all the values needed to fill the struct.Code:struct Test { int variable1; int variable 2; . . . int variable300; }
is there a way to dynamically fill the data without having to set them as
can we loop through the structures variables and fill them ?Code:Test.variable1 = String1; Test.variable2 = String2; . . . Test.variable300 = String300;
Thx
Yeah, there is:
Code:struct Test { int variable[300]; };
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"That is why you fail." - YodaOriginally Posted by alaash
Why don't you use an array or some container?
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actually the structure doesn't have the same variable type , it has arrays , and different variable types. in the example above , i was just trying to deliver the idea behind the question.
Anyways, i found the solution it can be done using union to merge to structs (the original structure , and another one containing just an array) where they will both write to the same memory thereby writing to the second struct will modify the first.
That won't work if the compiler inserts padding into structs. Practically, most compilers introduce padding by default for performance reasons, and the amount of padding between two consecutive elements in a struct is compiler-dependent. And that's assuming your structs are PoD (Plain Old Data). There is virtually no way your approach will work for non-PoD types, or if any of the struct members are non-PoD.
You could put all those members into a std::tuple ... but for 300 different types , it is somewhat unrealistic to write.
and compiling it would likely take hours. I seem to recall that compile time for tuples increases exponentially as you add more template parameters.
Well, okay. What on earth (or outside of it) is this structure?
Besides, if you can bear the tedious effort of declaring all those members, you can bear the tedious effort of assigning to them individually.
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Out of curiosity: What is this überstruct you're working with. I don't think I ever saw a struct, object or what have you with more than maybe 20 instance variables...
Okay I'm going to stop you right there. Whatever you were going to ask after that point is not particularly important. This is the primary problem right here.
300 is beyond excessive. That's beyond the 1 in a million chance that you might have stumbled upon the one situation where it actually makes sense to do something a certain unusual way. Straight up, that is not how to program, least of all how to program in C++.
You may as well be asking how to clean an entire airport runway with a toothbrush. We can't answer such a question except by suggesting that you need a different approach.
That said, you'll now need to give more information about what is in this structure. Also, how is this structure used? Is it a singleton, or are there many instances? Is it used polymorphically, or to represent more than one possible thing?
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