Scientists can train machines in different ways. In the early days of the era of artificial intelligence, programmers wrote hard-coded programs and input every logical possibility that machines might face and how to deal with it. When the system becomes complex, it becomes difficult to deal with the rules. To overcome this problem, machines can use data to learn how to deal with all situations in a given environment. The most important feature of having a strong artificial intelligence is that it has satisfactory data and considerable heterogeneity. For example, as long as a machine has enough words to learn, it can learn different languages. Artificial intelligence is a new frontier technology. Venture capitalists have invested billions of dollars in startups or artificial intelligence projects, and McKinsey estimates that artificial intelligence can drive at least double-digit growth rates in every industry. General AI, according to the rules of AI, decision tree AI and super AI are types of artificial intelligence.