What are the differences between javascript and c language?

Difference: 1. C language is mainly compiled into machine language, and JavaScript is mainly interpreted and executed as a script by the interpreter; 2. C language requires programmers to manually manage memory, while JS memory is handled by the interpreter. Managed; 3. C language is a statically typed language, and JS is a dynamically typed language; 4. There is no concept of closure in C language, but there is in JS.

The operating environment of this tutorial: windows7 system, javascript1.8.5&&c99 version, Dell G3 computer.

JavaScript ("JS" for short) is a lightweight, interpreted or just-in-time compiled programming language with function priority. Although it is famous as a scripting language for developing Web pages, it is also used in many non-browser environments. JavaScript is based on prototype programming, a multi-paradigm dynamic scripting language, and supports object-oriented, imperative, declarative, and functional programming paradigm.

C language is a process-oriented, abstract, general-purpose programming language that is widely used in low-level development. C language can compile and process low-level memory in a simple way. C language is an efficient programming language that only generates a small amount of machine language and can run without any operating environment support. Although the C language provides many low-level processing functions, it still maintains cross-platform characteristics. C language programs written in a standard specification can be executed on many computer platforms including operating platforms such as embedded processors and supercomputers. Compile.

The difference between javascript and c language

1. C language is mainly compiled into machine language, while JavaScript is mainly interpreted and executed as a script by the interpreter;

2. C language requires programmers to manually manage memory (mainly referring to the application and release of heap memory), while JavaScript memory is managed by the interpreter;

3. C language is a static type Language, that is, the data type of each variable is determined before the program is run, and cannot be changed at runtime. JavaScript is a dynamically typed language, and the data type of the variable can still be changed at runtime;

4. C language There is no concept of closure in JavaScript. Functions in JavaScript form closures with variables that are accessible when they are defined;

5. C language does not encapsulate "class member methods" and "class members (externally) Invisible), "class inheritance and polymorphism" and other object-oriented features are supported, and JavaScript can realize object-oriented inheritance, polymorphism and encapsulation through prototype chains and closures, realizing ECMAScript 2015 and above versions of JavaScript. It supports the definition of classes at the grammatical level;

6. C language can implement multi-threading by calling the system API, and can use multi-threading to improve the CPU utilization during blocking operations (mainly IO), while JavaScript Mainly single-threaded, JavaScript's possible blocking operations are completed by the asynchronous API provided by the JavaScript runtime.

Similarities between javascript and c language:

Some lexicon and syntax are the same. The design of JavaScript's lexical and syntax is based on Java, and the design of Java's lexical and syntax is based on C. The lexical and syntax that I think of for JavaScript, Java, C and C are the same:

1. Use a single equal sign as an assignment operator instead of an equality judgment operator, such as: a=b 1 represents "put The result of variable b 1 is assigned to variable a" instead of "the value of variable a is equal to the value of variable b 1";

2. The assignment operation is an expression and can be used as a value to participate in other operations, such as (a=b 1)>10;

3. The statement ends with a semicolon;

4.It starts with “0x” to represent the hexadecimal number;

5. Use "&", "|", "^", "!", "&&" and "||" as bitwise AND, bitwise OR, bitwise XOR, logical NOT, logical AND, and logical OR operations respectively. operator;

6, ternary operator composed of question mark and colon;

7, multiplication and division operators, addition and subtraction operators, comparison operators, logical and logical or operators, assignment The priority order of operators;

8. The syntax of function call is "function name (parameter 1, parameter 2, ...)";

9. Code blocks are placed in curly brackets Within;

10, if, for, while, do-while, switch-case, break syntax;

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