Why did I make an error when introducing the basic class in the index controller when I wrote the same basic class as my teacher?

Question

Why did I write the same basic class as my teacher and got an error when introducing the basic class in the index controller? Class 'think\controller' not found

大大卷 · Answer

This type of problem is relatively easy to solve, either the controller does not exist, or the path is wrong

PHP中文网 · Answer

Controller does not exist