&& students[i].grupa = gr Blockquote in above code, = is an assignment operator you need == for a comparison operator 2 solved C++: Cannot compare double from an array of structures to another double in if function [closed]
If subset is truly a subset of df and no additional rows have been omitted or added to df, filter using row names will work. xy <- data.frame(sub = rep(letters[1:3], 9), val = runif(9)) xy.sub <- xy[xy$sub %in% “b”, ] xy[!rownames(xy) %in% rownames(xy.sub), ] To match multiple columns, you can do xy[!(xy$val %in% xy.sub$val & … Read more
Is it guaranteed that the order of the pointers remains the same? (For example, I can imagine some GC trickery which also reorders the data.) In answer to this part of your question, it doesn’t look like it. See pkg unsafe linked below. If you want the memory address of a pointer, try the unsafe … Read more
C++ language has grammar for specifying classes, and the definition of a class can be shown by writing it in C++: class class_type {}; // an example of a class Unlike class types, fundamental types aren’t and cannot be defined using the C++ language and as such, it is not possible to show their definition … Read more