C expert programming notes-sizeof

# Include <stdio. h> # include <malloc. h> int main (void) {int * P; int * A; A = (int *) malloc (sizeof * P); * A = 1; printf ("% d \ n", * A); free (a); Return 0 ;}
 

The above sectionCode.

 
A = (int *) malloc (sizeof * P );
 

Generally, I have questions about the above line of code. Refer to the relevant information. The usage of sizeof is as follows:

1. Used for Data Types

Sizeof usage: sizeof (type)

The data type must be enclosed in parentheses. For example, sizeof (INT ).

2. Used for variables

Sizeof format: sizeof (var_name) or sizeof var_name

Variable names can be enclosed in parentheses. For example, sizeof (var_name) and sizeof var_name are all in the correct format.