C/C++ 定積分

資料來源: https://mp.weixin.qq.com/s/sactY0kCE6SBp4H-GFRCgA

GITHUB: https://github.com/jash-git/Jash-good-idea-20210419-001/tree/master/C%2B%2B%E5%AE%9A%E7%A9%8D%E5%88%86