for 循环是一种结构，表示执行此操作 n. 次".>

foreach 循环是一种结构，表示对这个 IEnumerable 中的 每个 值/对象执行此操作"

What is the major difference between for and foreach loops?

In which scenarios can we use for and not foreach and vice versa.

Would it be possible to show with a simple program?

Both seem the same to me. I can't differentiate them.

a for loop is a construct that says "perform this operation n. times".

a foreach loop is a construct that says "perform this operation against each value/object in this IEnumerable"