A variable is used in an opening sentence to indicate an ambiguous value (variable) or an alternative value (see function). These variables are usually represented by one English letter. If more than one English letter is used, it is easy to confuse them into multiplication of two variables. I, n, m, x, y and z are common variable names, where n, m and z often represent integers, and I often represent increasing variables in a loop (for example, in a sorting algorithm).
Summary of variable related knowledge points
1, variables and constants:
Variable: in a certain change process, the amount of numerical change is called variable; Generally speaking, in a changing process, there are two variables X and Y. If Y changes with the change of X, we say that X is an independent variable and Y is a dependent variable.
Constant: a quantity whose value remains constant during a certain change, which is called a constant.
2. The concept of tabular method: list a series of values of independent variables and corresponding values of dependent variables in a table to express the relationship between variables. This method of expressing the relationship between variables is called tabular method.
3. Supplementary explanation:
(1) When a table is used to represent the relationship between two variables, in general, the first row of the table represents the independent variable and the second row represents the dependent variable. According to the data in the table, we can get the information between two variables and predict their changing trend.
(2) When the table can be used to express the relationship between two variables, it can accurately point out the values of several groups of independent variables and dependent variables, but it can't fully reflect the relationship between the two variables, only part of them can be reflected. It is the key to solve the problem to obtain the information of the relationship between two variables from the data and find out the changing law.