Programming languages serve as the connection between human ideas and computer actions. Ideally, we could communicate with computers using everyday language, similar to scenes in science fiction movies. Technologies like Siri, Google Now, and Cortana have made progress towards this vision, but fully comprehending human language remains a complex challenge for computers. Natural languages, rich with ambiguity and nuances, aren't precisely suited for defining the strict logic required by algorithms.
To address this, computer scientists have created programming languages—specialized notations designed to express computations clearly and without ambiguity. These languages, such as Python, C++, and Java, have strict syntax (rules of structure) and semantics (meaning), enabling programmers to write instructions that computers can execute. Coding involves using these languages to formulate algorithms in a way that computers can understand.
High-level programming languages, including the ones mentioned, are designed for human readability and ease of use, while computers operate on a much simpler, binary language known as machine language. For example, a simple addition in Python, written as c = a + b, is easy for us to understand but needs translation into the binary operations that a computer's CPU can perform.
This translation from high-level to machine language is achieved through two main processes: compiling and interpreting. A compiler converts the entire program from a high-level language (source code) into machine language (executable code) all at once, allowing the computer's hardware to execute it directly. An interpreter, on the other hand, processes the program line by line, translating and executing each instruction on the fly without producing a separate machine language program.
The key difference between these two approaches is efficiency and flexibility. Compiled programs, once translated, run quickly since they are already in the computer's native language. Interpreted languages, however, offer more flexibility during development, allowing for immediate execution and testing of code, which can speed up the programming process.
High-level languages also provide portability. Unlike machine-specific binary code, a program written in a high-level language can run on various types of computers with the appropriate compiler or interpreter. This means the same Python program could run on both a laptop and a tablet, despite differences in their hardware, because both devices have Python interpreters.
In summary, programming languages are essential tools for communicating tasks to computers, crafted to minimize ambiguity and enhance clarity. The choice between compiling and interpreting depends on the program's needs and the development process, balancing speed against flexibility and ease of debugging.