Let's talk about the priority of data type: double & gtfloat & gtint & gtChar, that is, if you encounter something with higher priority than yourself, you will change it to a higher priority.

The first 10+'a'+i*f contains a double, so 10+'a' is still an int, and i*f is a double, and then the two are added together to form a double.

W*x is int type and char type is character. When calculating, it will be converted into int type by sacll code, so it is still int type. Then, after addition and subtraction, they all became double types.

You can ask me if you don't understand anything. I hope it can be adopted. Thank you.