There are many ways to sign in. The simple way is to use a pen and paper. For example, teachers in schools ask students to sign their names and count the number of people. There are many ways to sign in electronically, and punching in at work is another form of sign-in to prove a day's work.

Computer is a modern electronic computer for high-speed calculation, which can be used for numerical calculation and logical calculation, and also has the function of storage and memory. It is a modern intelligent electronic device that can run according to the program and automatically process massive data at high speed.