cpp_tips: address review comments

jxu · web-flow · commit edabef5c3b5f · 2024-11-04T09:34:28.000-05:00
#1383
diff --git a/src/others/cpp_tips.md b/src/others/cpp_tips.md
@@ -7,7 +7,7 @@ tags:
 
 ## Faster I/O
 
-- `std::ios_base::sync_with_stdio(false)`: by default, C++ works with C++ iostreams (like `std::cin`) and C style stdio streams (like `stdin`) by synchronizing them.
+- `std::ios_base::sync_with_stdio(false)`: by default, C++ works with C++ iostreams (like `std::cin`, may not apply to new C++23 `std::print`/`std::println`) and C style stdio streams (like `stdin`) by synchronizing them.
 Since you should never need C style I/O (like `scanf`, `printf`), in C++, disabling this synchronization will make C++ I/O competitive with C style `scanf`.
 - `std::cin.tie(0)`: By default, iostreams flush cout every time you read from cin, so that you will always display any output before reading any input.
 You can disable this automatic flushing to make I/O faster. The exception is for interactive problems with interleaved inputs and outputs, for which you can either not use `cin.tie(0)` or flush explicitly with `cout.flush()`/`cout.endl`.
@@ -19,9 +19,9 @@ References:
 ## Less Typing
 
 - `using namespace std;`: this saves lots of tedious typing of `std::` before all the standard library functions and objects. However, a blanket namespace import like this can cause name clashes, so don't name your variables or functions something common like `find` or anything from [this list](https://en.cppreference.com/w/cpp/symbol_index).
-- `#include <bits/stdc++.h>`: this is a catch-all implementation-defined header in g++ that avoids having a list of dozens of includes like `#include <vector>`, `#include <iostream>`, `#include <string>`, etc. It should work on any CP judge site, but it is not a standard header.
-- `#define int long long`: some people define `int` to always be (at least) 64-bit to avoid overflow issues, since most CP problems use numbers that fit in a 64-bit integer. However, be aware of unexpected issues:
+- `#include <bits/stdc++.h>`: this is a catch-all implementation-defined header in g++ that avoids having a list of dozens of includes like `#include <vector>`, `#include <iostream>`, `#include <string>`, etc. It should work on any CP judge site, but it is not a standard header. On your local machine, it can be pre-compiled to greatly save compilation time.
+- `#define int long long`: some people define `int` to always be (at least) 64-bit to avoid overflow issues, since most CP problems use numbers that fit in a 64-bit integer. However, this is **not recommended** because of many unexpected issues:
   - C++ requires `main` to be a function returning `int` and not `long long`, so use `signed main` as a workaround.
   - Function calls like `min(x, 0)` may complain that `0` is type `int`. 
-  - May require twice as much memory than `int` and make the program slower, which may be important in extremely time-critical code.
+  - Requires twice as much memory than `int` and may make the program slower, which may be important in extremely time-critical code.
   - Otherwise you can use `typedef long long ll` or use the appropriate fixed-width integer types like `int64_t`. 
