How related is source code to the machine code?

Question

Also,What is the difference between low-level and high-level programming languages?Thanks.

Answer 1

Machine code is hardware-specific instruction that directly controls the CPU. It is a numeric language not readable by humans.
https://en.m.wikipedia.org/wiki/Machine_code

The lowest level language that is used in programming, is Assembly, that is sort of a symbolic machine code. It has very basic elements like "store this number in that memory location".
https://en.m.wikipedia.org/wiki/Assembly_language

Higher level languages add more abstractions to explain to the computer in more human-like terms what to do. With high level languages, we can use a few keywords or function calls to initiate complex programming tasks.

Source code is the actual program, written in any programming language, be it low or high level. Source code is compiled or interpreted by the language runtime, so ultimately it ends up as machine code that your computer can execute directly.