C++ Syntax

&

In C++, & lets you pass by reference. You aren’t passing a pointer (?) - It’s like an alias for the OG object. Means you can access its properties with the . operator instead of ->

Strings

to_string() to turn objects into strings. You can do string += other_string string foo = 10 + "a" same as string bar =

Iterating

For maps

for (const auto& kv : m) {
    kv.first;  // key
    kv.second; // value
}

• Use const for reference to element in map. Means item is const. Can’t mutate key or value.
• Don’t use const so you can change the value, but still not the key (since keys are immutable)
• Use & to pass by reference. Without it, e.g. with just auto kv : m, you make a copy.