How can we build logic in programming ??

Program Logic

Program is a set of instruction. Logic is how to solve the problem. A program logic sets out what a project will do and how it will do it. It represents a project’s theory of change.
The program logic does this by visually representing a linear sequence of steps that need to occur for a project to meet its desired goals . This generally consists of identifying the inputs, activities, outputs, and outcomes. An important component of program logic is the identification of assumptions that link steps.

Though a program logic tends to reduce a complex problems into linear steps, it does provide a road map for your project. From this road map, you can monitor whether you keep to the road, or deviate, and if you do deviate, why this may have occurred.  This presents a valuable learning opportunity for any project.
A program logic should not replace a detailed project plan, but rather inform your project plan. A project plan will generally have more detailed steps and tasks than a program logic.