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std::map<int,int> mapy;
++mapy[5];
Is it safe to assume that mapy[5] will always be 1? I mean, will mapy[5] always get the default value of 0 before ‘++’, even if not explicitly declared, as in my code?
As soon as you access the map with the [] operator, if the key doesn’t exist it gets added. The int gets "value initialization" invoked – so it will get a value of 0.