Sailesh's answer is correct in that what you intend to build is a decision tree. There are many algorithms already for learning such trees such as e.g. Random Forests. You could e.g. try weka and see what is available there.
If you're more interested in evolutionary algorithms, I want to mention Genetic Programming. You can try for example our implementation in HeuristicLab. It can deal with numeric classes and attempts to find a formula (tree) that maps each row to its respective class using e.g. mean squared error (MSE) as fitness function.
There are also instance-based classification methods like nearest neighbor or kernel-based methods like support vector machines. Instance-based method also support multiple classes, but with kernel-methods you have to use one of the approaches you mentioned.