lst-0056-book.cpp
// https://godbolt.org/z/zMWo69974
#include <iostream>
int main() {
int count = 0;
auto plus1 = [count](int x) mutable { // count as a copy
std::cout << ++count; return x+1;
};
for(int i=0; i<5; ++i) {
plus1(i);
}
std::cout << "\n";
// Output: 12345
}