C does not have to be spaghetti code. C code can be modular and flexible if you apply the SOLID design principles. Too often design is just about personal preference. In this session we'll see that there are objective qualities that we can use to assess software design. We look at applying Single Responsibility, Open-Closed, Liskov Substitution, Interface Segregation and Dependency Inversion principles to C. SOLID gives good guidance on modularity and coupling; these principles are not just for programmers with an OO language. You can use the SOLID principles to build better C code.