The meaning of GL in computer _ essay

In the computer industry, there are usually several generations of languages to represent the development of language.

1GL or first-generation languages are languages that machine languages or machines can execute directly, that is, a string of 0 and 1. 2GL or second-generation languages are assembly language. A typical 2GL directive looks like this: The add12,8 Assembler converts assembly language into machine languages. 3GL or third-generation languages are "advanced" programming languages, such as Pl/i,c,java, which belong to this category.

In the computer industry, there are usually several generations of languages to represent the development of language. 1GL or first-generation languages are languages that machine languages or machines can execute directly, that is, a string of 0 and 1. 2GL or second-generation languages are assembly language. A typical 2GL directive looks like this: The ADD 12,8 Assembler converts assembly language into machine languages. 3GL or third-generation languages are "advanced" programming languages, such as Pl/i,c,java, which belong to this category. The following is an example of the Java language: public boolean handleevent (Event evt) {switch (evt.id) {case event.action_event: {if ("Try me". Equald (Evt.arg)) {The compiler converts a statement from a specific high-level programming language into a machine language. (In the Java example above, the output is called bytecode, which is then converted to the corresponding machine language by the Java Virtual machine that is part of the operating system platform.) To use 3GL requires a certain degree of programming knowledge. 4GL or fourth-generation languages are much closer to the natural language than 3GL. The language that accesses the database is often referred to as 4GL. The following is an example of a 4GL statement: EXTRACT all CUSTOMERS WHERE "PREVIOUS purchases" the total more THAN $1000 5GL or fifth-generation languages are programmed with visual or graphical interfaces to generate an original language, which The native language is usually compiled with a 3GL or 4GL language compiler. For example, Microsoft, Poland, IBM, and others have produced 5GL visual programming tools that can be used to develop applications in the Java language. Visual programming allows you to easily visualize the class dimension of object-oriented programming, and can assemble program components with some drag-and-drop icons [1]