finding a symmetrical substring

This is a clever (meaning pretty harsh) exercise. I think I have drafted a solution (not tested) but since it is a homework it is better to find the REASONING behind.

I assume this is a basic programming course, so I will use only basic instructions and will not focus on efficiency - it might complicate things a lot.

First thing, you are working with a string and searching substrings. So for the first thing you should scan the string char by char with a for cycle (let's say we use the variable i as counter).

Second thing, you obviously need to look subsequent characters in the string, so you will need a nested cycle (let's use variable j) that starst from the current value of the outer loop and scans until the end of the string, comparing the i-th carachet with the j-th.

Third, you need to find substrings, so you might need another nested cycle (let's use k) that when i-th and j-th characters are the same starts looking if the characters at the positions i+k and j+k are the same, and counts the equal characters.

Then, if you have more than 1 character you found the substrings. I left out most of the logic pointing out only the basic block-building reasoning behind the problem, the same reasoning I followed to draft the solution.

Think on this and try to write it down, see what goes wrong and do some trials, them eventually report us where you're stuck or wether you've benn successful.

Hope to be of help,
Denis