C4.5 is a software extension of the basic ID3 algorithm designed by Quinlan to address the following issues not dealt with by ID3:
Avoiding overfitting the data
Determining how deeply to grow a decision tree.
Reduced error pruning.
Rule post-pruning.
Handling continuous attributes.
e.g., temperature
Choosing an appropriate attribute selection measure.
Handling training data with missing attribute values.
Handling attributes with differing costs.
Improving computational efficiency.
It is installed for use on Grendel (grendel.icd.uregina.ca), but it may be set up on a local machine as follows: