What does the asterisk in the function mean?

In C language, the asterisk (*) has many meanings, one of which is the pointer. When you declare a pointer variable, you need to add an asterisk before the variable name, such as int *ptr. In a function, an asterisk can be used to access a value in a memory address pointed by a pointer to another variable. This way can realize the function of passing values between variables in a function.

In addition to pointers, asterisks can also be used to define the return type of functions. For example, if a function returns a pointer to an integer, you can add an asterisk before the function name, such as int* functionName (). This method can also realize the function of manipulating pointer variables inside the function.

In the function parameter list, an asterisk can be used to indicate that the parameter is a pointer type. For example, int* arr means that arr is a pointer variable that points to an integer type. If you want to change the value pointed by the pointer in the function, you need to use the address of the pointer when calling the function, that is&; Arr. This method can avoid copying the way variables pass parameters in functions, thus improving the efficiency of the program.