To start with, here are a few points you should work on:
1. Reading the values, the for loop should start from 0 instead of 1.
2. Reading the values, if you read them into n and l, they will be overwritten with each for loop.
You should read the values into the arrays.
Try to print the values in the arrays after reading them, just to make sure you've taken the inut correctly.
3. Smallest and highest variables should be initialised. Assign the first element of the scores array to both the variables.
4. For loop to find highest and to find smallest should be independent of one another. One loop should not be inside another.
(you can use the same loop to find both as well. Just keep both if conditions inside the same for loop)
Any case, definitely go through this tutorial
http://www.cplusplus.com/doc/tutorial/arrays/