4 computer languages
- 2. Types of Programming Languages • Machine Languages • Assembly Languages • High Level Languages Bali Thorat
- 3. Machine Languages • A machine language consists of the numeric codes for the operations that a particular computer can execute directly. • The codes are strings of 0s and 1s, or binary digits (“bits”), which are frequently converted both from and to hexadecimal (base 16) for human viewing and modification. • Machine language instructions typically use some bits to represent operations, such as addition, and some to represent operands, or perhaps the location of the next instruction. • Machine language is difficult to read and write, since it does not resemble conventional mathematical notation or human language, and its codes vary from computer to computer. Bali Thorat
- 4. Assembly language • Assembly language is one level above machine language. • It uses short mnemonic codes for instructions and allows the programmer to introduce names for blocks of memory that hold data. • One might thus write “add pay, total” instead of “0110101100101000” for an instruction that adds two numbers. • Assembly language is designed to be easily translated into machine language. • Although blocks of data may be referred to by name instead of by their machine addresses, assembly language does not provide more sophisticated means of organizing complex information. • Like machine language, assembly language requires detailed knowledge of internal computer architecture. • It is useful when such details are important, as in programming a computer to interact with peripheral devices (printers, scanners, storage devices, and so forth). Bali Thorat
- 5. High Level Languages • A high-level language (HLL) is a programming language such as C, FORTRAN, or Pascal that enables a programmer to write programs that are more or less independent of a particular type of computer. • Such languages are considered high-level because they are closer to human languages and further from machine languages. Bali Thorat
- 6. Assembler • An assembler translates assembly language programs into machine code. • The output of an assembler is called an object file, which contains a combination of machine instructions as well as the data required to place these instructions in memory. Bali Thorat
- 7. Linker • Linker is a computer program that links and merges various object files together in order to make an executable file. • All these files might have been compiled by separate assemblers. • The major task of a linker is to search and locate referenced module/routines in a program and to determine the memory location where these codes will be loaded, making the program instruction to have absolute references. Bali Thorat
- 8. Loader • Loader is a part of operating system and is responsible for loading executable files into memory and execute them. • It calculates the size of a program (instructions and data) and creates memory space for it. • It initializes various registers to initiate execution. Bali Thorat
- 9. Interpreter • An interpreter translates high-level language into low-level machine language. • An interpreter reads a statement from the input, converts it to an intermediate code, executes it, then takes the next statement in sequence. • If an error occurs, an interpreter stops execution and reports it. Bali Thorat
- 10. Compiler • Compiler, translates high-level language into low-level machine language. • A compiler reads the whole source code at once, creates tokens, checks semantics, generates intermediate code, executes the whole program and may involve many passes. • Compiler reads the whole program even if it encounters several errors. Bali Thorat
- 11. • User writes a program in C language (high-level language). • The C compiler, compiles the program and translates it to assembly program (low-level language). • An assembler then translates the assembly program into machine code (object). • A linker tool is used to link all the parts of the program together for execution (executable machine code). • A loader loads all of them into memory and then the program is executed. Bali Thorat