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c++vectorsegmentation-faultdeque

How to use a vector of deques of a parameterized class in C++?

I'm trying to use a vector of deques of a custom class. I've got this:

std::vector<std::deque<ParamClass<Type1,Type2>>> lines;

Where ParamClass is a parameterized class with two class parameters. The above line is in the header (as a private variable) of another class. The constructor of that class doesn't do anything to variable lines.

Later on in the code I try:

std::cout << lines.at(0).size() << std::endl;

This should print 0 (as nothing has been added to the deques in the vector. However, I'm getting a segfault. Do I have to somehow "initialize" the deques or something?

Solution

  • You are accessing element 0 but you haven't added anything so at(0) tries to access illegal memory

    You need to make sure lines.size() > 0 first