[Stage 1] Specification decision stage

 The first step is to define what to program. If this is not well thought out, even if a code change occurs in one place, the other code may have to be rewritten, and eventually all may be rewritten.

[Stage 2] Coding stage

 The stage of writing code according to the specifications. It is also a stage where many programmer qualities are asked. In other words, whether or not a program that performs the same operation is not redundant and it is thought that bugs can be easily found depends greatly on the ability of the programmer.

[Stage 3] Quality confirmation and maintenance stage

 Confirmation of the operation of the completed program and the correction stage accompanying specification changes. Even program development is the most difficult stage. It’s a patience and time-consuming task that needs to prove that the program works correctly under all conditions and doesn’t crash or break the system, so it tries every possible input.