A variable is a quantity whose value can be changed during the running of a program.

A constant is a quantity whose value is not allowed to change during the running of a program.

Variables must be described. The purpose of description is to let the program know the class of variables and allocate corresponding number of storage units to variables.

The variable must be described first, and then the variable name cannot be reserved for the system.

What do you mean by variables?

A variable refers to a quantity that can change at any time during the running of a program.

A variable is a temporary storage location for data in a program. You can use one or more variables in your code, where you can store words, values, dates and attributes. Variables are very useful because they allow you to give each piece of data used in a program a short and memorable name. Variables can store the data input by the user when the program is running (for example, use the InputBox function to display a dialog box on the screen, and then save the text typed by the user into variables), the result of a specific operation, and a piece of data to be displayed on the form. In short, variables are simple tools for tracking almost all types of information.

Explanatory variables What are explanatory variables?

For example, in the equation Y=X, the independent variable x is the explanatory variable and y is the explained variable. For example, in economics, the total social output Y=C+I+G+xm. In this equation, consumption (c) investment (I) *** expenditure (g) import (XM) is the explanatory variable used to describe the total output, and the total output is the explained variable.

What is a characteristic variable?

Variables are the characteristics of objects in statistical research. In quantity symbols, immutable quantity symbols are called constants or parameters, and variable quantity symbols are called variables. Various indicators constructed by variable digital signs are also called variables. It can be qualitative or quantitative, and quantitative variables can be discrete or continuous. When studying the relationship between variables in social science, one variable is usually called independent variable (independent variable) and the other variable is called dependent variable (dependent variable). Variables include various quantitative indicators and all statistical indicators, expressed in digital form, but excluding quality indicators.

Characteristic variables are relative to random variables.

What do you mean by adding * before the variable?

If defined, it means that the variable is a pointer, and if called, it means taking the value of the variable.

What is the meaning of' ||' in variables in JS?

Logical OR operator (||)

Result = expression1|| expression2;

If one or both expressions are equal to True, the result is True.

JScript uses the following rules to convert non-Boolean values to Boolean values:

1. All objects are considered real.

2. A string is considered false if and only if it is empty.

3.null and undefined are considered false.

4. Only the number of 0 is false.

What are the main variables?

There are a lot of data in the program to represent the state of the program. Some data will change in value during the program running, and some data will not change in value during the program running. These data are called variables and constants respectively in the program. In the program, you can choose to use variables or constants according to whether the data changes during the program running. The syntax for declaring variables is: type var-name.

Where type is the data type of the variable and var-name is the name of the variable.

The following are some examples of variable declarations:

int x； Declare x as an integer variable.

Even number; Declare a number as a double-precision variable

Check Elvis Presley; Declare Wang as a character variable

String s; Declare s as a string variable

The above example uses plastic, double precision, characters and strings. If several variables are of the same type, they can be uniformly declared in the following simple format, and the variables are separated by commas.