Classification of functions (1) Library functions: Functions provided by the C system; (2) User-defined function: Function defined by the user; (3) Returns the function of the returns to the caller, indicating the function type ( That is, the type of return value); (4) Function without return value: Do not return a function value, indicating the type of air (VOID) type; (5) a function: The main adjustment function transmits data to the transferred function; (6) no Number: No data transfer between the main adjustment function and the called function; (7) Internal function: functions that can only be used in this source file; (8) External function: The function can be used in the entire source program.
2. General Form of Function Definition [Extern / Static] Type Description Function Name ([Distake]) Inquiode Options.
3. General Form of Function Description [EXTERN] Type Description Function Name ([Distance]);
4. General Form of Functions Call ([Real Mesel])
5. The parameters of the function are divided into two types of parameters and inform, and the formal parameter appears in the function definition. In the function call, the value of the argument will be transmitted to the values when the function is called.
6. The value of the function is the return value of the function, which is returned by the return statement in the function.
7. The array name is not performed as a function parameter for address transmission. Conversion and argument actually for two names of the same array. Therefore, the value of the array group changes, and the value of the array array has also changed.
8. In the C language, the recursive calls of the function of the function are allowed.
9. Classification of variables, names, variable scopes, and variables of variables can be stored in three aspects. In the second chapter, the data type of the variable is mainly introduced, which is described in this chapter.
10. The scope of the variable refers to the valid range of the variable in the program and is divided into local variables and global variables.
11. The storage type of the variable refers to the storage mode of the variable in memory, divided into still static storage and dynamic storage, indicating the survival of the variable.
12. Variable Classification Characteristic Table Storage Mode Storage Type Desifter Where to Define Value Default Field Before Assignment Field Assignment You Primer Type Dynamic Storage Auto Variable AUTO Register Variable REGISTER Function or Composite Scheduler Deconsive Its function or The basic type INT or CHAR external variable extern function Outside the entire source program The entire source program Static local variable static function or the composite statement, the static global variable static function, the entire source program is defined in the definition of its function or composite statement Its source file 0 any type
