Most C++-projects I dealt with are neither clean nor performant. I rather follow clean code to improve maintainability and get things done than to optimize for

Most C++-projects I dealt with are neither clean nor performant. I rather follow clean code to improve maintainability and get things done than to optimize for performance. It’s also easier to find bottlenecks in a well readable and testable code base than in a premature-optimized one. However it is true that the more abstractions and indirections used software gets slower. Also these examples are too basic to make a real-world suggestion: never assume sonething is slow in a large project because of indirection or something…always get a profiler involved and run tests with time requirements to identify and fix slow running parts of a program.