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#include <iostream>
#include <list>
#include <forward_list>
/*
*
* 9.31
*
* A lot of comments here but i had to do it to clear it up in my head
*/
int main () {
std::list<int> vi = {0,1,2,3,4,5,6,7,8,9};
auto iter = vi.begin(); // get begin
while (iter != vi.end()) { // when begin is not at the end
if (*iter % 2 == 1) { // when it's odd
iter = vi.insert(iter, *iter); // insert whatever is at *iter before iter and return iterator where the new value was inserted
++iter; // advance past what was inserted
++iter; // advance past the element we checked for odd/even(ness)
} else // when even
iter = vi.erase(iter); // remove the even value, return iterator to element after the erased element
}
std::forward_list<int> fli = {0,1,2,3,4,5,6,7,8,9};
auto beg = fli.begin(); // get begin
auto bbeg = fli.before_begin(); // get before begin
while (beg != fli.end()) { // while beg is not at the end
if (*beg % 2 == 1) { // when odd
bbeg = fli.insert_after(bbeg, *beg); // insert *beg after bbeg, returns iterator to inserted element
++beg; // advance beg to next element to be checked
++bbeg; // advance bbeg to follow beg one value behind
} else // when it's even
beg = fli.erase_after(bbeg); // erase element after bbeg (the one at beg). Returns iterator to element after erased one (aka next one to be checked)
}
for(auto &a : vi) {
std::cout << a << std::endl;
}
for(auto &a : fli) {
std::cout << a << std::endl;
}
return 0;
}
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