我尝试使用本教程下载g ++的最新版本，并将版本号从4.7更改为最新的（相信是）8.1。但是我收到以下错误
Error: No available formula with the name "gcc81"
==> Searching for a previously deleted formula (in the last month)...
Warning: homebrew/core is shallow clone. To get complete history run:
git -C "$(brew --repo homebrew/core)" fetch --unshallow
Error: No previously deleted formula found.
==> Searching for similarly named formulae...
==> Searching local taps...
Error: No similarly named formulae found.
==> Searching taps...
==> Searching taps on GitHub...
Error: No formulae found in taps.
有人知道如何更新我的g ++版本吗？这是我尝试查找当前版本时得到的。
g++ --version …